<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2022 Workiva-->
<!--r:01446e88-7d39-4080-86dd-371f274163d4,g:154ad7ce-ecbd-418f-a52d-5603f70b2a15-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:roleRef roleURI="http://www.pliantrx.com/role/Cover" xlink:type="simple" xlink:href="plrx-20220630.xsd#Cover"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/Cover" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_CoverAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType_c742f78b-a183-48fe-9cf7-6124fc93683c" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentType"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_DocumentType_c742f78b-a183-48fe-9cf7-6124fc93683c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentQuarterlyReport_20b0d57a-7478-48f4-9da2-23882869d47f" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentQuarterlyReport"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_DocumentQuarterlyReport_20b0d57a-7478-48f4-9da2-23882869d47f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate_17ad1b50-460b-45cb-8452-f440d00c2d80" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentPeriodEndDate"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_DocumentPeriodEndDate_17ad1b50-460b-45cb-8452-f440d00c2d80" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentTransitionReport_c757bddb-2554-41d3-a0bd-52209992bdee" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentTransitionReport"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_DocumentTransitionReport_c757bddb-2554-41d3-a0bd-52209992bdee" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFileNumber_590e7bde-56c1-4486-afd7-9ac3a552958b" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityFileNumber"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntityFileNumber_590e7bde-56c1-4486-afd7-9ac3a552958b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityRegistrantName_41d48fbe-e681-4d1e-87f8-4319ae341b91" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityRegistrantName"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntityRegistrantName_41d48fbe-e681-4d1e-87f8-4319ae341b91" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityIncorporationStateCountryCode_5d978ae1-fa12-4952-86bd-588eb39ca9de" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityIncorporationStateCountryCode"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntityIncorporationStateCountryCode_5d978ae1-fa12-4952-86bd-588eb39ca9de" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityTaxIdentificationNumber_50f4ea22-da4c-4510-86c2-f410eda42409" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityTaxIdentificationNumber"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntityTaxIdentificationNumber_50f4ea22-da4c-4510-86c2-f410eda42409" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressAddressLine1_8440afa8-c107-456e-9aab-9197825ac76a" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityAddressAddressLine1"/>
    <link:presentationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntityAddressAddressLine1_8440afa8-c107-456e-9aab-9197825ac76a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown_75b00e03-5470-47c9-8b0e-e34b2b9fbcfc" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityAddressCityOrTown"/>
    <link:presentationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntityAddressCityOrTown_75b00e03-5470-47c9-8b0e-e34b2b9fbcfc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince_5357943e-407a-4dd1-a73c-849f3ec75b60" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityAddressStateOrProvince"/>
    <link:presentationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntityAddressStateOrProvince_5357943e-407a-4dd1-a73c-849f3ec75b60" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressPostalZipCode_05838604-5bed-4333-8fa0-7945690a6509" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityAddressPostalZipCode"/>
    <link:presentationArc order="12" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntityAddressPostalZipCode_05838604-5bed-4333-8fa0-7945690a6509" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CityAreaCode_0c1daac3-8c2f-4605-8151-ccb2daf7d2c6" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_CityAreaCode"/>
    <link:presentationArc order="13" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_CityAreaCode_0c1daac3-8c2f-4605-8151-ccb2daf7d2c6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_LocalPhoneNumber_b18ff8b8-78eb-48d7-89cd-f961147b6502" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_LocalPhoneNumber"/>
    <link:presentationArc order="14" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_LocalPhoneNumber_b18ff8b8-78eb-48d7-89cd-f961147b6502" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle_139af8b2-af1c-47ce-8368-b58a6d55df89" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_Security12bTitle"/>
    <link:presentationArc order="15" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_Security12bTitle_139af8b2-af1c-47ce-8368-b58a6d55df89" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_TradingSymbol_f1c202f6-2310-44da-8b26-243823ee899a" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_TradingSymbol"/>
    <link:presentationArc order="16" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_TradingSymbol_f1c202f6-2310-44da-8b26-243823ee899a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_SecurityExchangeName_d472fca0-3616-4499-91ea-1693a8c4b6b2" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_SecurityExchangeName"/>
    <link:presentationArc order="17" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_SecurityExchangeName_d472fca0-3616-4499-91ea-1693a8c4b6b2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCurrentReportingStatus_d70b4ca5-e9d0-4393-95be-9b1b7b5edd3d" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityCurrentReportingStatus"/>
    <link:presentationArc order="18" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntityCurrentReportingStatus_d70b4ca5-e9d0-4393-95be-9b1b7b5edd3d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityInteractiveDataCurrent_e965f21e-bb09-4078-a20c-820bb4ec861b" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityInteractiveDataCurrent"/>
    <link:presentationArc order="19" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntityInteractiveDataCurrent_e965f21e-bb09-4078-a20c-820bb4ec861b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityFilerCategory_c899a76e-2036-4b54-8a40-acfaca96b7c3" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityFilerCategory"/>
    <link:presentationArc order="20" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntityFilerCategory_c899a76e-2036-4b54-8a40-acfaca96b7c3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntitySmallBusiness_abac8887-5424-45fe-8c06-318842dad7d5" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntitySmallBusiness"/>
    <link:presentationArc order="21" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntitySmallBusiness_abac8887-5424-45fe-8c06-318842dad7d5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityEmergingGrowthCompany_68500d90-009d-41a8-aa52-401e11d6cf8d" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityEmergingGrowthCompany"/>
    <link:presentationArc order="22" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntityEmergingGrowthCompany_68500d90-009d-41a8-aa52-401e11d6cf8d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityShellCompany_5420e57c-5f45-42da-844c-0054d7665ade" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityShellCompany"/>
    <link:presentationArc order="23" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntityShellCompany_5420e57c-5f45-42da-844c-0054d7665ade" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding_f511c5b8-00c2-4b86-960c-74efff12b83f" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:presentationArc order="24" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntityCommonStockSharesOutstanding_f511c5b8-00c2-4b86-960c-74efff12b83f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AmendmentFlag_ec9ff651-e136-4173-8d55-71ab1487abbc" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_AmendmentFlag"/>
    <link:presentationArc order="25" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_AmendmentFlag_ec9ff651-e136-4173-8d55-71ab1487abbc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalYearFocus_6dfa4146-25be-4679-8a8f-9e6bc469fc3e" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentFiscalYearFocus"/>
    <link:presentationArc order="26" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_DocumentFiscalYearFocus_6dfa4146-25be-4679-8a8f-9e6bc469fc3e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentFiscalPeriodFocus_2f0d9918-2720-41d5-9337-e9bf1fe04158" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_DocumentFiscalPeriodFocus"/>
    <link:presentationArc order="27" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_DocumentFiscalPeriodFocus_2f0d9918-2720-41d5-9337-e9bf1fe04158" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCentralIndexKey_7f12c458-9f61-4b89-8eac-8dadd9eb9e46" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_EntityCentralIndexKey"/>
    <link:presentationArc order="28" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_EntityCentralIndexKey_7f12c458-9f61-4b89-8eac-8dadd9eb9e46" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_dei_CurrentFiscalYearEndDate_563f5007-224b-47f8-9ea6-31f39dc0a60e" xlink:href="https://xbrl.sec.gov/dei/2022/dei-2022.xsd#dei_CurrentFiscalYearEndDate"/>
    <link:presentationArc order="29" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_dei_CoverAbstract_c2243aba-bb13-42c0-ac1e-4ae66cf47ea6" xlink:to="loc_dei_CurrentFiscalYearEndDate_563f5007-224b-47f8-9ea6-31f39dc0a60e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/CondensedBalanceSheetsUnaudited" xlink:type="simple" xlink:href="plrx-20220630.xsd#CondensedBalanceSheetsUnaudited"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/CondensedBalanceSheetsUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfFinancialPositionAbstract_9dd69308-92a7-4161-8ea6-f17a8a9ebaa5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementOfFinancialPositionAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract_27d7a3dd-402a-44a6-9825-2ef03267d5c7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_9dd69308-92a7-4161-8ea6-f17a8a9ebaa5" xlink:to="loc_us-gaap_AssetsAbstract_27d7a3dd-402a-44a6-9825-2ef03267d5c7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrentAbstract_2fa472b4-0b11-4b4e-8c3e-67252df4d3dc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsCurrentAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_27d7a3dd-402a-44a6-9825-2ef03267d5c7" xlink:to="loc_us-gaap_AssetsCurrentAbstract_2fa472b4-0b11-4b4e-8c3e-67252df4d3dc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_e51dcb4d-6542-4904-bfa9-3dcdf97e2173" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashAndCashEquivalentsAtCarryingValue"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_2fa472b4-0b11-4b4e-8c3e-67252df4d3dc" xlink:to="loc_us-gaap_CashAndCashEquivalentsAtCarryingValue_e51dcb4d-6542-4904-bfa9-3dcdf97e2173" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestments_063c6f77-fdf3-47c9-8ab0-d1ea9eee58f5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShortTermInvestments"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_2fa472b4-0b11-4b4e-8c3e-67252df4d3dc" xlink:to="loc_us-gaap_ShortTermInvestments_063c6f77-fdf3-47c9-8ab0-d1ea9eee58f5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNetCurrent_198f2d9c-cc52-43c2-a1cb-fee66c25872d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountsReceivableNetCurrent"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_2fa472b4-0b11-4b4e-8c3e-67252df4d3dc" xlink:to="loc_us-gaap_AccountsReceivableNetCurrent_198f2d9c-cc52-43c2-a1cb-fee66c25872d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesReceivable_4af1467a-4b51-4547-bf23-f8af88f26611" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxesReceivable"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_2fa472b4-0b11-4b4e-8c3e-67252df4d3dc" xlink:to="loc_us-gaap_IncomeTaxesReceivable_4af1467a-4b51-4547-bf23-f8af88f26611" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_ed328a6b-8476-4515-8ab3-ae415b23a06f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_2fa472b4-0b11-4b4e-8c3e-67252df4d3dc" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_ed328a6b-8476-4515-8ab3-ae415b23a06f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsCurrent_b58d5a86-fa2b-47c2-9141-1e89ec8f27be" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsCurrent"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsCurrentAbstract_2fa472b4-0b11-4b4e-8c3e-67252df4d3dc" xlink:to="loc_us-gaap_AssetsCurrent_b58d5a86-fa2b-47c2-9141-1e89ec8f27be" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_fb212999-56ea-4fd0-8851-bc13d5ce052b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_27d7a3dd-402a-44a6-9825-2ef03267d5c7" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_fb212999-56ea-4fd0-8851-bc13d5ce052b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_a4017012-5c89-4fe8-8a6d-e6b559af7c92" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseRightOfUseAsset"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_27d7a3dd-402a-44a6-9825-2ef03267d5c7" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_a4017012-5c89-4fe8-8a6d-e6b559af7c92" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsNoncurrent_b616a7e0-ae23-4e67-b383-a96cafaa2a99" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherAssetsNoncurrent"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_27d7a3dd-402a-44a6-9825-2ef03267d5c7" xlink:to="loc_us-gaap_OtherAssetsNoncurrent_b616a7e0-ae23-4e67-b383-a96cafaa2a99" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_5d9e5881-3906-409b-be53-7493393c8f6c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Assets"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AssetsAbstract_27d7a3dd-402a-44a6-9825-2ef03267d5c7" xlink:to="loc_us-gaap_Assets_5d9e5881-3906-409b-be53-7493393c8f6c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_7314f4f5-b86b-4e0c-9a6d-f294f62ce334" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_9dd69308-92a7-4161-8ea6-f17a8a9ebaa5" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_7314f4f5-b86b-4e0c-9a6d-f294f62ce334" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract_4bdb2e8a-b51e-4bea-ba6e-8500c9a0eee9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_7314f4f5-b86b-4e0c-9a6d-f294f62ce334" xlink:to="loc_us-gaap_LiabilitiesCurrentAbstract_4bdb2e8a-b51e-4bea-ba6e-8500c9a0eee9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableCurrent_b6dcb766-8769-4f92-a3fc-103197edeee9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountsPayableCurrent"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_4bdb2e8a-b51e-4bea-ba6e-8500c9a0eee9" xlink:to="loc_us-gaap_AccountsPayableCurrent_b6dcb766-8769-4f92-a3fc-103197edeee9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_58bb63f5-1ebb-45a7-a338-cdd848cb914b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_4bdb2e8a-b51e-4bea-ba6e-8500c9a0eee9" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_58bb63f5-1ebb-45a7-a338-cdd848cb914b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_fe0069f2-44ac-4065-a813-80e64eac856e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiabilityCurrent"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_4bdb2e8a-b51e-4bea-ba6e-8500c9a0eee9" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_fe0069f2-44ac-4065-a813-80e64eac856e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrent_55ae5665-37b0-4e41-8e9c-20d70efb7861" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesCurrent"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract_4bdb2e8a-b51e-4bea-ba6e-8500c9a0eee9" xlink:to="loc_us-gaap_LiabilitiesCurrent_55ae5665-37b0-4e41-8e9c-20d70efb7861" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_7a27b706-a12e-4166-8116-48fe85829125" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_7314f4f5-b86b-4e0c-9a6d-f294f62ce334" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_7a27b706-a12e-4166-8116-48fe85829125" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_0e7d46e4-afa7-4c8b-8ded-931184535dd0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebt"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_7314f4f5-b86b-4e0c-9a6d-f294f62ce334" xlink:to="loc_us-gaap_LongTermDebt_0e7d46e4-afa7-4c8b-8ded-931184535dd0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Liabilities_e9a6be2e-0f07-4f91-b3d6-1dcdc496e410" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Liabilities"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_7314f4f5-b86b-4e0c-9a6d-f294f62ce334" xlink:to="loc_us-gaap_Liabilities_e9a6be2e-0f07-4f91-b3d6-1dcdc496e410" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityAbstract_9dcd6904-c373-4a54-99f7-40a3d015b511" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquityAbstract"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_7314f4f5-b86b-4e0c-9a6d-f294f62ce334" xlink:to="loc_us-gaap_StockholdersEquityAbstract_9dcd6904-c373-4a54-99f7-40a3d015b511" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockValue_54dd49d5-90ca-4784-8086-1c0da9c33f2c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockValue"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_9dcd6904-c373-4a54-99f7-40a3d015b511" xlink:to="loc_us-gaap_CommonStockValue_54dd49d5-90ca-4784-8086-1c0da9c33f2c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalCommonStock_833ec384-2983-4ff3-819f-6965975b5cc5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdditionalPaidInCapitalCommonStock"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_9dcd6904-c373-4a54-99f7-40a3d015b511" xlink:to="loc_us-gaap_AdditionalPaidInCapitalCommonStock_833ec384-2983-4ff3-819f-6965975b5cc5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsAccumulatedDeficit_d5c4ee0a-33bd-4a12-9c34-14ff0e2c6b44" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetainedEarningsAccumulatedDeficit"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_9dcd6904-c373-4a54-99f7-40a3d015b511" xlink:to="loc_us-gaap_RetainedEarningsAccumulatedDeficit_d5c4ee0a-33bd-4a12-9c34-14ff0e2c6b44" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_bacaba47-4075-44da-8f9d-bcf1d3ff01f9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_9dcd6904-c373-4a54-99f7-40a3d015b511" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_bacaba47-4075-44da-8f9d-bcf1d3ff01f9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_ec913182-f5be-4bed-9113-52445b21c1df" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StockholdersEquityAbstract_9dcd6904-c373-4a54-99f7-40a3d015b511" xlink:to="loc_us-gaap_StockholdersEquity_ec913182-f5be-4bed-9113-52445b21c1df" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity_12ff89e2-287f-4ec8-ac53-c4632922cf23" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_7314f4f5-b86b-4e0c-9a6d-f294f62ce334" xlink:to="loc_us-gaap_LiabilitiesAndStockholdersEquity_12ff89e2-287f-4ec8-ac53-c4632922cf23" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/CondensedBalanceSheetsUnauditedParenthetical" xlink:type="simple" xlink:href="plrx-20220630.xsd#CondensedBalanceSheetsUnauditedParenthetical"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/CondensedBalanceSheetsUnauditedParenthetical" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfFinancialPositionAbstract_b8b093df-3f42-43c7-b537-7a45d17473a3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementOfFinancialPositionAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_cc38b5c1-55a9-4341-86ac-a946cfdc47d2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_b8b093df-3f42-43c7-b537-7a45d17473a3" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_cc38b5c1-55a9-4341-86ac-a946cfdc47d2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_e1ff55db-c14d-4f74-a6c6-457f90eb798c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_b8b093df-3f42-43c7-b537-7a45d17473a3" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_e1ff55db-c14d-4f74-a6c6-457f90eb798c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesIssued_e100f833-4c29-454b-940a-be87c0ced29b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockSharesIssued"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_b8b093df-3f42-43c7-b537-7a45d17473a3" xlink:to="loc_us-gaap_CommonStockSharesIssued_e100f833-4c29-454b-940a-be87c0ced29b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_c91ebb1d-14b6-4778-9cdc-cb0f32b95295" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfFinancialPositionAbstract_b8b093df-3f42-43c7-b537-7a45d17473a3" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_c91ebb1d-14b6-4778-9cdc-cb0f32b95295" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/CondensedStatementsofOperationsandComprehensiveLossUnaudited" xlink:type="simple" xlink:href="plrx-20220630.xsd#CondensedStatementsofOperationsandComprehensiveLossUnaudited"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/CondensedStatementsofOperationsandComprehensiveLossUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementAbstract_9be789a4-52b1-453d-9dab-8e46e458a94d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_8b34a599-68f1-4c52-aad2-6c1aa89292ff" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_9be789a4-52b1-453d-9dab-8e46e458a94d" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_8b34a599-68f1-4c52-aad2-6c1aa89292ff" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpensesAbstract_ecef2034-8251-4360-93d5-541b8dfd24a0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingExpensesAbstract"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_9be789a4-52b1-453d-9dab-8e46e458a94d" xlink:to="loc_us-gaap_OperatingExpensesAbstract_ecef2034-8251-4360-93d5-541b8dfd24a0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_a66a3d45-4a80-48c8-a171-6867f916aa54" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingExpensesAbstract_ecef2034-8251-4360-93d5-541b8dfd24a0" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_a66a3d45-4a80-48c8-a171-6867f916aa54" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_5319dd12-3a9a-4c79-8689-80d54056f421" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingExpensesAbstract_ecef2034-8251-4360-93d5-541b8dfd24a0" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_5319dd12-3a9a-4c79-8689-80d54056f421" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_e6b1836e-e1d5-4713-a4ac-a6ead064bc7e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingExpenses"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingExpensesAbstract_ecef2034-8251-4360-93d5-541b8dfd24a0" xlink:to="loc_us-gaap_OperatingExpenses_e6b1836e-e1d5-4713-a4ac-a6ead064bc7e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedTotalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_8ecaf94e-d8ca-49b4-ada9-6eca93fbc6fb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_9be789a4-52b1-453d-9dab-8e46e458a94d" xlink:to="loc_us-gaap_OperatingIncomeLoss_8ecaf94e-d8ca-49b4-ada9-6eca93fbc6fb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_InterestAndOtherIncomeNet_b32dc831-94fb-449d-98d2-260f2b0cfc0d" xlink:href="plrx-20220630.xsd#plrx_InterestAndOtherIncomeNet"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_9be789a4-52b1-453d-9dab-8e46e458a94d" xlink:to="loc_plrx_InterestAndOtherIncomeNet_b32dc831-94fb-449d-98d2-260f2b0cfc0d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_99a4203f-83bf-421f-a6e3-de869a653694" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_9be789a4-52b1-453d-9dab-8e46e458a94d" xlink:to="loc_us-gaap_NetIncomeLoss_99a4203f-83bf-421f-a6e3-de869a653694" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_3a834fa5-b06c-4fe6-bde1-e432a85760fc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_9be789a4-52b1-453d-9dab-8e46e458a94d" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_3a834fa5-b06c-4fe6-bde1-e432a85760fc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_9a5df316-fa80-4f94-8e8c-ac97e0c8110d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_9be789a4-52b1-453d-9dab-8e46e458a94d" xlink:to="loc_us-gaap_EarningsPerShareAbstract_9a5df316-fa80-4f94-8e8c-ac97e0c8110d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_8513f950-636b-430f-9f51-cea3baa43ca8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_9a5df316-fa80-4f94-8e8c-ac97e0c8110d" xlink:to="loc_us-gaap_EarningsPerShareBasic_8513f950-636b-430f-9f51-cea3baa43ca8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_2d5dd96c-7eb0-4f0b-b16b-998cb57932d0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_9a5df316-fa80-4f94-8e8c-ac97e0c8110d" xlink:to="loc_us-gaap_EarningsPerShareDiluted_2d5dd96c-7eb0-4f0b-b16b-998cb57932d0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_44f5215d-2eab-4478-8ebd-8ab3fab24798" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_9be789a4-52b1-453d-9dab-8e46e458a94d" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_44f5215d-2eab-4478-8ebd-8ab3fab24798" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_2600df0f-378a-48ec-82ad-4b753d2646fe" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_44f5215d-2eab-4478-8ebd-8ab3fab24798" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_2600df0f-378a-48ec-82ad-4b753d2646fe" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_cc3bfddd-7960-4d73-baf6-a2f434f6951c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_44f5215d-2eab-4478-8ebd-8ab3fab24798" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_cc3bfddd-7960-4d73-baf6-a2f434f6951c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_7725f978-c1bf-4200-8e00-1d2558d1fc33" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ComprehensiveIncomeNetOfTaxAbstract"/>
    <link:presentationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementAbstract_9be789a4-52b1-453d-9dab-8e46e458a94d" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_7725f978-c1bf-4200-8e00-1d2558d1fc33" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_ca5da5dd-84e3-4732-8060-1be8d6051cd7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_7725f978-c1bf-4200-8e00-1d2558d1fc33" xlink:to="loc_us-gaap_NetIncomeLoss_ca5da5dd-84e3-4732-8060-1be8d6051cd7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_4957128d-5e90-4894-a5d0-89dae644a5f9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_7725f978-c1bf-4200-8e00-1d2558d1fc33" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_4957128d-5e90-4894-a5d0-89dae644a5f9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_91c2d16d-ec30-40a9-9f93-98f38e9d8861" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_7725f978-c1bf-4200-8e00-1d2558d1fc33" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_91c2d16d-ec30-40a9-9f93-98f38e9d8861" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComprehensiveIncomeNetOfTax_bc41a4b6-ccca-4abe-bfd2-3609909dabc0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ComprehensiveIncomeNetOfTax"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ComprehensiveIncomeNetOfTaxAbstract_7725f978-c1bf-4200-8e00-1d2558d1fc33" xlink:to="loc_us-gaap_ComprehensiveIncomeNetOfTax_bc41a4b6-ccca-4abe-bfd2-3609909dabc0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/CondensedStatementsofStockholdersEquityUnaudited" xlink:type="simple" xlink:href="plrx-20220630.xsd#CondensedStatementsofStockholdersEquityUnaudited"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/CondensedStatementsofStockholdersEquityUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfStockholdersEquityAbstract_3b6d4fce-64ff-4d38-9801-58bff8be34a8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementOfStockholdersEquityAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_567a01b8-1d4d-4b26-97f1-68d023162df4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfStockholdersEquityAbstract_3b6d4fce-64ff-4d38-9801-58bff8be34a8" xlink:to="loc_us-gaap_StatementTable_567a01b8-1d4d-4b26-97f1-68d023162df4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_cec00853-579e-493e-9827-da6ef9e1f704" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_567a01b8-1d4d-4b26-97f1-68d023162df4" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_cec00853-579e-493e-9827-da6ef9e1f704" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_bad59caa-8d2e-4a9e-90c8-3cb26f61547c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityComponentDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_cec00853-579e-493e-9827-da6ef9e1f704" xlink:to="loc_us-gaap_EquityComponentDomain_bad59caa-8d2e-4a9e-90c8-3cb26f61547c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_96f0b56c-1c4c-4f05-b396-b30468d0031c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityComponentDomain_bad59caa-8d2e-4a9e-90c8-3cb26f61547c" xlink:to="loc_us-gaap_CommonStockMember_96f0b56c-1c4c-4f05-b396-b30468d0031c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_5cb7bdd4-c986-4755-835f-81ce8bdfe8d9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityComponentDomain_bad59caa-8d2e-4a9e-90c8-3cb26f61547c" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_5cb7bdd4-c986-4755-835f-81ce8bdfe8d9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_6594af94-9be6-414c-86a5-afcd8baa157e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityComponentDomain_bad59caa-8d2e-4a9e-90c8-3cb26f61547c" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_6594af94-9be6-414c-86a5-afcd8baa157e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_2bd942a0-730e-4b83-8816-affa251a906f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RetainedEarningsMember"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityComponentDomain_bad59caa-8d2e-4a9e-90c8-3cb26f61547c" xlink:to="loc_us-gaap_RetainedEarningsMember_2bd942a0-730e-4b83-8816-affa251a906f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_a9fe4020-c398-4742-aa6a-28819411634f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementTable_567a01b8-1d4d-4b26-97f1-68d023162df4" xlink:to="loc_us-gaap_StatementLineItems_a9fe4020-c398-4742-aa6a-28819411634f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e18d3a57-6d51-4f22-bc08-1de109fae936" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementLineItems_a9fe4020-c398-4742-aa6a-28819411634f" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e18d3a57-6d51-4f22-bc08-1de109fae936" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_9129a92e-dcd8-4977-bb47-a53d2b1d66e5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e18d3a57-6d51-4f22-bc08-1de109fae936" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_9129a92e-dcd8-4977-bb47-a53d2b1d66e5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_c5194bff-36b3-414f-866e-4eeb67f6c52a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e18d3a57-6d51-4f22-bc08-1de109fae936" xlink:to="loc_us-gaap_StockholdersEquity_c5194bff-36b3-414f-866e-4eeb67f6c52a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_53b268bb-b873-4c3c-9412-aea31c1fe32b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e18d3a57-6d51-4f22-bc08-1de109fae936" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures_53b268bb-b873-4c3c-9412-aea31c1fe32b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_8fadece0-b889-41d8-ad19-d10a992c1ac0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e18d3a57-6d51-4f22-bc08-1de109fae936" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardNetOfForfeitures_8fadece0-b889-41d8-ad19-d10a992c1ac0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_8e410aae-e058-43fb-aaa6-11e4a09b4a2d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e18d3a57-6d51-4f22-bc08-1de109fae936" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_8e410aae-e058-43fb-aaa6-11e4a09b4a2d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_281e0622-57ac-4536-8404-cd2e4331921e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e18d3a57-6d51-4f22-bc08-1de109fae936" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_281e0622-57ac-4536-8404-cd2e4331921e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_a5726bb9-4cff-4176-9a44-fa86406f6264" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e18d3a57-6d51-4f22-bc08-1de109fae936" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_a5726bb9-4cff-4176-9a44-fa86406f6264" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_db40c8da-5e23-4516-8b88-e57c6c62ca56" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e18d3a57-6d51-4f22-bc08-1de109fae936" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_db40c8da-5e23-4516-8b88-e57c6c62ca56" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_af5c7eac-cbcc-456c-8c25-6313e5c288b0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>
    <link:presentationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e18d3a57-6d51-4f22-bc08-1de109fae936" xlink:to="loc_us-gaap_NetIncomeLoss_af5c7eac-cbcc-456c-8c25-6313e5c288b0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_5ee3fa8d-14c9-4674-b941-1e3cc493e1da" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:presentationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e18d3a57-6d51-4f22-bc08-1de109fae936" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_5ee3fa8d-14c9-4674-b941-1e3cc493e1da" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_6ea2acb9-95f1-4689-b1c6-8dc71654e3dc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquity"/>
    <link:presentationArc order="11" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_e18d3a57-6d51-4f22-bc08-1de109fae936" xlink:to="loc_us-gaap_StockholdersEquity_6ea2acb9-95f1-4689-b1c6-8dc71654e3dc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/CondensedStatementsofCashFlowsUnaudited" xlink:type="simple" xlink:href="plrx-20220630.xsd#CondensedStatementsofCashFlowsUnaudited"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/CondensedStatementsofCashFlowsUnaudited" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfCashFlowsAbstract_b750bf3d-179f-4747-aaa0-34d3e90ff8d0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementOfCashFlowsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_b38d5c62-cfc7-4687-b5fa-0e6adab41818" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_b750bf3d-179f-4747-aaa0-34d3e90ff8d0" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_b38d5c62-cfc7-4687-b5fa-0e6adab41818" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_5898c915-3cd1-45ce-834e-abffe195462b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_b38d5c62-cfc7-4687-b5fa-0e6adab41818" xlink:to="loc_us-gaap_NetIncomeLoss_5898c915-3cd1-45ce-834e-abffe195462b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_aa5c4ee0-4765-4d2c-a8f3-3427752d55ca" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_b38d5c62-cfc7-4687-b5fa-0e6adab41818" xlink:to="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_aa5c4ee0-4765-4d2c-a8f3-3427752d55ca" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_5dd6064f-9107-4db8-b42a-d2c815c92ad3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Depreciation"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_aa5c4ee0-4765-4d2c-a8f3-3427752d55ca" xlink:to="loc_us-gaap_Depreciation_5dd6064f-9107-4db8-b42a-d2c815c92ad3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_f7fbf819-7f51-4bd5-9812-088eaa2b425c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensation"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_aa5c4ee0-4765-4d2c-a8f3-3427752d55ca" xlink:to="loc_us-gaap_ShareBasedCompensation_f7fbf819-7f51-4bd5-9812-088eaa2b425c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense_56700769-577b-46d4-87fd-4acb8459d572" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_aa5c4ee0-4765-4d2c-a8f3-3427752d55ca" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAssetAmortizationExpense_56700769-577b-46d4-87fd-4acb8459d572" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_OtherLosses_8d0d3e5f-402b-4a72-9a04-fa247a40de1c" xlink:href="plrx-20220630.xsd#plrx_OtherLosses"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_aa5c4ee0-4765-4d2c-a8f3-3427752d55ca" xlink:to="loc_plrx_OtherLosses_8d0d3e5f-402b-4a72-9a04-fa247a40de1c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_75a5fedd-5c6d-48ae-bb3b-71cb28346251" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_aa5c4ee0-4765-4d2c-a8f3-3427752d55ca" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_75a5fedd-5c6d-48ae-bb3b-71cb28346251" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_8d22040b-8b41-436c-b537-395111a86324" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_75a5fedd-5c6d-48ae-bb3b-71cb28346251" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_8d22040b-8b41-436c-b537-395111a86324" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_8e915270-8fd3-4935-8f6a-65cbb9c103e5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_75a5fedd-5c6d-48ae-bb3b-71cb28346251" xlink:to="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_8e915270-8fd3-4935-8f6a-65cbb9c103e5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherNoncurrentAssets_0572d23a-ecc1-45ce-9466-b2f066826d8f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInOtherNoncurrentAssets"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_75a5fedd-5c6d-48ae-bb3b-71cb28346251" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherNoncurrentAssets_0572d23a-ecc1-45ce-9466-b2f066826d8f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsPayable_00eeee63-ef1a-4e68-ab6e-19d9d9838c13" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInAccountsPayable"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_75a5fedd-5c6d-48ae-bb3b-71cb28346251" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsPayable_00eeee63-ef1a-4e68-ab6e-19d9d9838c13" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_3e82da64-cfa7-404d-802b-73752bde0059" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInAccruedLiabilities"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_75a5fedd-5c6d-48ae-bb3b-71cb28346251" xlink:to="loc_us-gaap_IncreaseDecreaseInAccruedLiabilities_3e82da64-cfa7-404d-802b-73752bde0059" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities_4e5cb2bb-2334-4b41-bae7-093f93e09e9f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_75a5fedd-5c6d-48ae-bb3b-71cb28346251" xlink:to="loc_us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities_4e5cb2bb-2334-4b41-bae7-093f93e09e9f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingLeaseLiability_dd66c56e-4816-46cc-952e-69d3c8b9595c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncreaseDecreaseInOperatingLeaseLiability"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_75a5fedd-5c6d-48ae-bb3b-71cb28346251" xlink:to="loc_us-gaap_IncreaseDecreaseInOperatingLeaseLiability_dd66c56e-4816-46cc-952e-69d3c8b9595c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_a14f8017-2cec-4ca7-ab6f-5f2435becc33" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_b38d5c62-cfc7-4687-b5fa-0e6adab41818" xlink:to="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_a14f8017-2cec-4ca7-ab6f-5f2435becc33" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_9e8a593a-e76e-4423-8a64-d9f1a8082ab5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_b750bf3d-179f-4747-aaa0-34d3e90ff8d0" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_9e8a593a-e76e-4423-8a64-d9f1a8082ab5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireShortTermInvestments_165fbe5b-df2e-4add-b862-ca2eab84109d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquireShortTermInvestments"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_9e8a593a-e76e-4423-8a64-d9f1a8082ab5" xlink:to="loc_us-gaap_PaymentsToAcquireShortTermInvestments_165fbe5b-df2e-4add-b862-ca2eab84109d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfShorttermInvestments_e31116f1-a7ae-4a49-b65b-cda68d55db5c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfShorttermInvestments"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_9e8a593a-e76e-4423-8a64-d9f1a8082ab5" xlink:to="loc_us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfShorttermInvestments_e31116f1-a7ae-4a49-b65b-cda68d55db5c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_47a9b60e-e5ab-4908-8f9b-b1dfb9c38ee7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_9e8a593a-e76e-4423-8a64-d9f1a8082ab5" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_47a9b60e-e5ab-4908-8f9b-b1dfb9c38ee7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_7ac67327-9c3e-441d-b6cc-0cf4d1cfaa12" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_9e8a593a-e76e-4423-8a64-d9f1a8082ab5" xlink:to="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_7ac67327-9c3e-441d-b6cc-0cf4d1cfaa12" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_744fcffd-97f7-4a8b-ab92-b546437e08c1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_b750bf3d-179f-4747-aaa0-34d3e90ff8d0" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_744fcffd-97f7-4a8b-ab92-b546437e08c1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromStockOptionsExercised_33edf658-7096-4e6a-95ec-aa58a46c4c1c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromStockOptionsExercised"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_744fcffd-97f7-4a8b-ab92-b546437e08c1" xlink:to="loc_us-gaap_ProceedsFromStockOptionsExercised_33edf658-7096-4e6a-95ec-aa58a46c4c1c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_PaymentsOfDeferredOfferingCosts_24e3d908-02b2-4503-b713-5a309325f4a9" xlink:href="plrx-20220630.xsd#plrx_PaymentsOfDeferredOfferingCosts"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_744fcffd-97f7-4a8b-ab92-b546437e08c1" xlink:to="loc_plrx_PaymentsOfDeferredOfferingCosts_24e3d908-02b2-4503-b713-5a309325f4a9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsOfDebtIssuanceCosts_33c6c184-d40a-4a5b-b00b-9dbee7a5eade" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PaymentsOfDebtIssuanceCosts"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_744fcffd-97f7-4a8b-ab92-b546437e08c1" xlink:to="loc_us-gaap_PaymentsOfDebtIssuanceCosts_33c6c184-d40a-4a5b-b00b-9dbee7a5eade" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedTerseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfDebt_75220020-6d9f-4a79-bcea-3a6f8f90c0fb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromIssuanceOfDebt"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_744fcffd-97f7-4a8b-ab92-b546437e08c1" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfDebt_75220020-6d9f-4a79-bcea-3a6f8f90c0fb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_4976b3e2-9d9f-4731-a873-9c8ada2e4fae" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_744fcffd-97f7-4a8b-ab92-b546437e08c1" xlink:to="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities_4976b3e2-9d9f-4731-a873-9c8ada2e4fae" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_1b3e838a-e9d8-4e85-a220-539abe7ef005" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_b750bf3d-179f-4747-aaa0-34d3e90ff8d0" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect_1b3e838a-e9d8-4e85-a220-539abe7ef005" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_8d8706bd-0161-430c-a3ea-83f321eebcde" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_b750bf3d-179f-4747-aaa0-34d3e90ff8d0" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_8d8706bd-0161-430c-a3ea-83f321eebcde" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_c997b3e2-ea36-44ad-a28b-7b02ecf53f8b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_b750bf3d-179f-4747-aaa0-34d3e90ff8d0" xlink:to="loc_us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents_c997b3e2-ea36-44ad-a28b-7b02ecf53f8b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_SupplementalCashFlowDisclosuresAbstract_b48dd452-cd73-44c9-bb02-4a6cd00dd59f" xlink:href="plrx-20220630.xsd#plrx_SupplementalCashFlowDisclosuresAbstract"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_b750bf3d-179f-4747-aaa0-34d3e90ff8d0" xlink:to="loc_plrx_SupplementalCashFlowDisclosuresAbstract_b48dd452-cd73-44c9-bb02-4a6cd00dd59f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestPaidNet_9358c66b-56c6-4e93-abe3-38a716f78e93" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InterestPaidNet"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_plrx_SupplementalCashFlowDisclosuresAbstract_b48dd452-cd73-44c9-bb02-4a6cd00dd59f" xlink:to="loc_us-gaap_InterestPaidNet_9358c66b-56c6-4e93-abe3-38a716f78e93" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalCashFlowElementsAbstract_2b4894f5-3e3b-4a18-8489-eabc008c2b05" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SupplementalCashFlowElementsAbstract"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_b750bf3d-179f-4747-aaa0-34d3e90ff8d0" xlink:to="loc_us-gaap_SupplementalCashFlowElementsAbstract_2b4894f5-3e3b-4a18-8489-eabc008c2b05" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_68811133-c3c7-439e-8ad7-3c362e5f0cc3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CapitalExpendituresIncurredButNotYetPaid"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SupplementalCashFlowElementsAbstract_2b4894f5-3e3b-4a18-8489-eabc008c2b05" xlink:to="loc_us-gaap_CapitalExpendituresIncurredButNotYetPaid_68811133-c3c7-439e-8ad7-3c362e5f0cc3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_ReclassificationOfRestrictedStockAwardsFromLiabilitiesToCommonStockUponVesting_a07e1e15-3fb5-4524-98c1-87eb21ee8701" xlink:href="plrx-20220630.xsd#plrx_ReclassificationOfRestrictedStockAwardsFromLiabilitiesToCommonStockUponVesting"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SupplementalCashFlowElementsAbstract_2b4894f5-3e3b-4a18-8489-eabc008c2b05" xlink:to="loc_plrx_ReclassificationOfRestrictedStockAwardsFromLiabilitiesToCommonStockUponVesting_a07e1e15-3fb5-4524-98c1-87eb21ee8701" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrealizedGainLossOnInvestments_59d2e83d-c5c1-4e1f-acae-077f5ea9255f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_UnrealizedGainLossOnInvestments"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SupplementalCashFlowElementsAbstract_2b4894f5-3e3b-4a18-8489-eabc008c2b05" xlink:to="loc_us-gaap_UnrealizedGainLossOnInvestments_59d2e83d-c5c1-4e1f-acae-077f5ea9255f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/OrganizationandDescriptionofBusiness" xlink:type="simple" xlink:href="plrx-20220630.xsd#OrganizationandDescriptionofBusiness"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/OrganizationandDescriptionofBusiness" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_68062b31-2981-4695-b345-000638a6792a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessDescriptionAndBasisOfPresentationTextBlock_35cbe003-bfc9-49c7-b610-59a1f4fb5440" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BusinessDescriptionAndBasisOfPresentationTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_68062b31-2981-4695-b345-000638a6792a" xlink:to="loc_us-gaap_BusinessDescriptionAndBasisOfPresentationTextBlock_35cbe003-bfc9-49c7-b610-59a1f4fb5440" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/SummaryofSignificantAccountingPolicies" xlink:type="simple" xlink:href="plrx-20220630.xsd#SummaryofSignificantAccountingPolicies"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/SummaryofSignificantAccountingPolicies" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingPoliciesAbstract_6545aba2-23d1-449f-9f31-2b58daaf3162" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountingPoliciesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SignificantAccountingPoliciesTextBlock_a0a5da3b-fcd3-4c58-8846-65379be565ee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SignificantAccountingPoliciesTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccountingPoliciesAbstract_6545aba2-23d1-449f-9f31-2b58daaf3162" xlink:to="loc_us-gaap_SignificantAccountingPoliciesTextBlock_a0a5da3b-fcd3-4c58-8846-65379be565ee" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/SummaryofSignificantAccountingPoliciesPolicies" xlink:type="simple" xlink:href="plrx-20220630.xsd#SummaryofSignificantAccountingPoliciesPolicies"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/SummaryofSignificantAccountingPoliciesPolicies" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingPoliciesAbstract_a8cdf832-5052-4d66-8d18-609d2c407e82" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountingPoliciesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BasisOfAccountingPolicyPolicyTextBlock_2a146b6e-b7ce-4032-b69b-61192d541277" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BasisOfAccountingPolicyPolicyTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccountingPoliciesAbstract_a8cdf832-5052-4d66-8d18-609d2c407e82" xlink:to="loc_us-gaap_BasisOfAccountingPolicyPolicyTextBlock_2a146b6e-b7ce-4032-b69b-61192d541277" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UseOfEstimates_339973ce-a68e-4830-a15f-7af52cfa5aef" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_UseOfEstimates"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccountingPoliciesAbstract_a8cdf832-5052-4d66-8d18-609d2c407e82" xlink:to="loc_us-gaap_UseOfEstimates_339973ce-a68e-4830-a15f-7af52cfa5aef" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/FinancialInstruments" xlink:type="simple" xlink:href="plrx-20220630.xsd#FinancialInstruments"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/FinancialInstruments" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresAbstract_c22a5be5-a3e9-4bee-b83e-fe0c6b0c5e65" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueDisclosuresAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresTextBlock_36828755-9ebf-4981-940a-440c2e200836" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueDisclosuresTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueDisclosuresAbstract_c22a5be5-a3e9-4bee-b83e-fe0c6b0c5e65" xlink:to="loc_us-gaap_FairValueDisclosuresTextBlock_36828755-9ebf-4981-940a-440c2e200836" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/FinancialInstrumentsTables" xlink:type="simple" xlink:href="plrx-20220630.xsd#FinancialInstrumentsTables"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/FinancialInstrumentsTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresAbstract_5e17a0b5-d51f-46e5-b0f9-3198e37a8092" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueDisclosuresAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCashCashEquivalentsAndShortTermInvestmentsTableTextBlock_842ee88f-bfce-4119-9faf-4abe33bb774f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfCashCashEquivalentsAndShortTermInvestmentsTableTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueDisclosuresAbstract_5e17a0b5-d51f-46e5-b0f9-3198e37a8092" xlink:to="loc_us-gaap_ScheduleOfCashCashEquivalentsAndShortTermInvestmentsTableTextBlock_842ee88f-bfce-4119-9faf-4abe33bb774f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/FinancialInstrumentsSummaryofCashandCashEquivalentsMoneyMarketFundsandShorttermInvestmentsbySignificantInvestmentCategoryDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#FinancialInstrumentsSummaryofCashandCashEquivalentsMoneyMarketFundsandShorttermInvestmentsbySignificantInvestmentCategoryDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/FinancialInstrumentsSummaryofCashandCashEquivalentsMoneyMarketFundsandShorttermInvestmentsbySignificantInvestmentCategoryDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresAbstract_6e6b5e83-c841-4751-865f-9ccc6ef80a11" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueDisclosuresAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_3831c661-2fea-49e4-81d0-4fbdb834b246" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtSecuritiesAvailableForSaleTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueDisclosuresAbstract_6e6b5e83-c841-4751-865f-9ccc6ef80a11" xlink:to="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_3831c661-2fea-49e4-81d0-4fbdb834b246" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_58a93719-88d7-4338-a502-e0eb4c2cacea" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_3831c661-2fea-49e4-81d0-4fbdb834b246" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_58a93719-88d7-4338-a502-e0eb4c2cacea" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d24fa0cd-27ef-448e-9022-fc182ade10bd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_58a93719-88d7-4338-a502-e0eb4c2cacea" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d24fa0cd-27ef-448e-9022-fc182ade10bd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_58b6ee86-49a3-42f0-b5d6-d1ceb8cf0f16" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d24fa0cd-27ef-448e-9022-fc182ade10bd" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_58b6ee86-49a3-42f0-b5d6-d1ceb8cf0f16" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_b86e7e3d-bf55-4ed3-bad5-3c7f2945fcd3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_d24fa0cd-27ef-448e-9022-fc182ade10bd" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_b86e7e3d-bf55-4ed3-bad5-3c7f2945fcd3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAndCashEquivalentsAxis_fda9e7b0-dace-4965-9ea7-1e9e31029a41" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CashAndCashEquivalentsAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_3831c661-2fea-49e4-81d0-4fbdb834b246" xlink:to="loc_us-gaap_CashAndCashEquivalentsAxis_fda9e7b0-dace-4965-9ea7-1e9e31029a41" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_dcce5c00-0680-4b23-b453-a1887bb835fa" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CashAndCashEquivalentsAxis_fda9e7b0-dace-4965-9ea7-1e9e31029a41" xlink:to="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_dcce5c00-0680-4b23-b453-a1887bb835fa" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MoneyMarketFundsMember_e90387c8-c0c3-4162-97b4-556b7248edf8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_MoneyMarketFundsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_dcce5c00-0680-4b23-b453-a1887bb835fa" xlink:to="loc_us-gaap_MoneyMarketFundsMember_e90387c8-c0c3-4162-97b4-556b7248edf8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_28ef0d37-9ec0-4c5d-9f03-d95259734b8c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_dcce5c00-0680-4b23-b453-a1887bb835fa" xlink:to="loc_us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_28ef0d37-9ec0-4c5d-9f03-d95259734b8c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_75517f3d-cbc6-42f7-b2f1-ae2293bc63ec" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_3831c661-2fea-49e4-81d0-4fbdb834b246" xlink:to="loc_us-gaap_InvestmentTypeAxis_75517f3d-cbc6-42f7-b2f1-ae2293bc63ec" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_a239ae59-e3e9-4620-bb9e-fee734703ed8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InvestmentTypeAxis_75517f3d-cbc6-42f7-b2f1-ae2293bc63ec" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_a239ae59-e3e9-4620-bb9e-fee734703ed8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateDebtSecuritiesMember_68058772-c03e-4951-b650-f938b754da9c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CorporateDebtSecuritiesMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_a239ae59-e3e9-4620-bb9e-fee734703ed8" xlink:to="loc_us-gaap_CorporateDebtSecuritiesMember_68058772-c03e-4951-b650-f938b754da9c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_69b2d089-4e99-45de-857e-18220aad4e7f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleTable_3831c661-2fea-49e4-81d0-4fbdb834b246" xlink:to="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_69b2d089-4e99-45de-857e-18220aad4e7f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_aa1a6e9e-334a-476c-9da7-da03fcd5ac3f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_69b2d089-4e99-45de-857e-18220aad4e7f" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_aa1a6e9e-334a-476c-9da7-da03fcd5ac3f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedGain_a339dd5c-4a4d-4d3f-99c4-e049fdab72f5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedGain"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_69b2d089-4e99-45de-857e-18220aad4e7f" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedGain_a339dd5c-4a4d-4d3f-99c4-e049fdab72f5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedLoss_648e8ec9-bb08-466a-98d7-c0780c364028" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedLoss"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_69b2d089-4e99-45de-857e-18220aad4e7f" xlink:to="loc_us-gaap_AvailableForSaleDebtSecuritiesGrossUnrealizedLoss_648e8ec9-bb08-466a-98d7-c0780c364028" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_405e0a79-6842-4e92-a5b4-a681ee483226" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AvailableForSaleSecuritiesDebtSecurities"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_69b2d089-4e99-45de-857e-18220aad4e7f" xlink:to="loc_us-gaap_AvailableForSaleSecuritiesDebtSecurities_405e0a79-6842-4e92-a5b4-a681ee483226" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/FinancialInstrumentsNarrativeDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#FinancialInstrumentsNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/FinancialInstrumentsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresAbstract_3f592489-b0fc-44be-80aa-742bb7366f1a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueDisclosuresAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_d765778c-13e6-4061-98f7-1e80d6d2dd01" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByBalanceSheetGroupingTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueDisclosuresAbstract_3f592489-b0fc-44be-80aa-742bb7366f1a" xlink:to="loc_us-gaap_FairValueByBalanceSheetGroupingTable_d765778c-13e6-4061-98f7-1e80d6d2dd01" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_19d67497-6ea2-45af-a62b-a185a9a6beb4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_d765778c-13e6-4061-98f7-1e80d6d2dd01" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_19d67497-6ea2-45af-a62b-a185a9a6beb4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_0acbdcd5-4aa7-4b05-9f7a-5dd6e66d15df" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementFrequencyDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_19d67497-6ea2-45af-a62b-a185a9a6beb4" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_0acbdcd5-4aa7-4b05-9f7a-5dd6e66d15df" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_2070b95f-71b4-42b9-b985-0da59911e49f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsRecurringMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_0acbdcd5-4aa7-4b05-9f7a-5dd6e66d15df" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_2070b95f-71b4-42b9-b985-0da59911e49f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_66335028-8938-4ecd-b532-b81e15f34c04" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueMeasurementsNonrecurringMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_0acbdcd5-4aa7-4b05-9f7a-5dd6e66d15df" xlink:to="loc_us-gaap_FairValueMeasurementsNonrecurringMember_66335028-8938-4ecd-b532-b81e15f34c04" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_e5198b3e-a277-41f1-bb02-5d0958a0d38d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueByBalanceSheetGroupingTable_d765778c-13e6-4061-98f7-1e80d6d2dd01" xlink:to="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_e5198b3e-a277-41f1-bb02-5d0958a0d38d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialLiabilitiesFairValueDisclosure_e5cb88b1-3887-4b92-a86f-860e886a843f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_FinancialLiabilitiesFairValueDisclosure"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_e5198b3e-a277-41f1-bb02-5d0958a0d38d" xlink:to="loc_us-gaap_FinancialLiabilitiesFairValueDisclosure_e5cb88b1-3887-4b92-a86f-860e886a843f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_5c641af1-11e9-4492-a314-1b361b6601dc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_e5198b3e-a277-41f1-bb02-5d0958a0d38d" xlink:to="loc_us-gaap_AssetsFairValueDisclosure_5c641af1-11e9-4492-a314-1b361b6601dc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/PropertyandEquipmentnet" xlink:type="simple" xlink:href="plrx-20220630.xsd#PropertyandEquipmentnet"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/PropertyandEquipmentnet" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAbstract_dea5d17d-1724-4fee-bb45-42912aa7d55e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_6b5598b7-54ce-4f1d-9822-a2c2ebe3d3ed" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_dea5d17d-1724-4fee-bb45-42912aa7d55e" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock_6b5598b7-54ce-4f1d-9822-a2c2ebe3d3ed" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/PropertyandEquipmentnetTables" xlink:type="simple" xlink:href="plrx-20220630.xsd#PropertyandEquipmentnetTables"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/PropertyandEquipmentnetTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAbstract_37221102-4d80-433a-81f7-2d019018ad73" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTextBlock_b5374116-f6d4-41ca-abb2-2a6529ad75cc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_37221102-4d80-433a-81f7-2d019018ad73" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTextBlock_b5374116-f6d4-41ca-abb2-2a6529ad75cc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/PropertyandEquipmentnetScheduleofPropertyandEquipmentDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#PropertyandEquipmentnetScheduleofPropertyandEquipmentDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/PropertyandEquipmentnetScheduleofPropertyandEquipmentDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAbstract_f5919a52-b9b5-4392-b000-2d780520f905" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_6f0bdd4f-ae2b-4675-abc6-051c8778fd4c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_f5919a52-b9b5-4392-b000-2d780520f905" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_6f0bdd4f-ae2b-4675-abc6-051c8778fd4c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_4e0ed8c5-c1a2-47e6-89b5-a10b92db2b46" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_6f0bdd4f-ae2b-4675-abc6-051c8778fd4c" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_4e0ed8c5-c1a2-47e6-89b5-a10b92db2b46" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01461b7e-5d2a-4c34-846f-843d378ad8cd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_4e0ed8c5-c1a2-47e6-89b5-a10b92db2b46" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01461b7e-5d2a-4c34-846f-843d378ad8cd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_ComputerEquipmentAndSoftwareMember_8bc29442-06f9-4c96-9ef2-f695855f01bc" xlink:href="plrx-20220630.xsd#plrx_ComputerEquipmentAndSoftwareMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01461b7e-5d2a-4c34-846f-843d378ad8cd" xlink:to="loc_plrx_ComputerEquipmentAndSoftwareMember_8bc29442-06f9-4c96-9ef2-f695855f01bc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquipmentMember_b7b553b0-2798-4759-bf17-35399be4ae4f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquipmentMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01461b7e-5d2a-4c34-846f-843d378ad8cd" xlink:to="loc_us-gaap_EquipmentMember_b7b553b0-2798-4759-bf17-35399be4ae4f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_97de34a3-4c1c-48d0-a8c4-386254803675" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeaseholdImprovementsMember"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01461b7e-5d2a-4c34-846f-843d378ad8cd" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_97de34a3-4c1c-48d0-a8c4-386254803675" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConstructionInProgressMember_e6ff1b70-90f6-408a-96b1-d96d07228db8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ConstructionInProgressMember"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01461b7e-5d2a-4c34-846f-843d378ad8cd" xlink:to="loc_us-gaap_ConstructionInProgressMember_e6ff1b70-90f6-408a-96b1-d96d07228db8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_6c01c331-21e8-4478-8578-2e57d7b9145c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_6f0bdd4f-ae2b-4675-abc6-051c8778fd4c" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentLineItems_6c01c331-21e8-4478-8578-2e57d7b9145c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_4abad76c-a034-4128-b741-ae3c07a992fc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_6c01c331-21e8-4478-8578-2e57d7b9145c" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_4abad76c-a034-4128-b741-ae3c07a992fc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_b3b255f4-2bb4-433c-bbaa-f2b37c0626ec" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_6c01c331-21e8-4478-8578-2e57d7b9145c" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_b3b255f4-2bb4-433c-bbaa-f2b37c0626ec" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_7cb414df-3eba-425b-af12-78ab61108d95" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_6c01c331-21e8-4478-8578-2e57d7b9145c" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_7cb414df-3eba-425b-af12-78ab61108d95" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/PropertyandEquipmentnetNarrativeDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#PropertyandEquipmentnetNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/PropertyandEquipmentnetNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentAbstract_0b83043b-0ea7-4eaf-8b99-46140e5e8e34" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PropertyPlantAndEquipmentAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_a63482d0-52bf-4bda-8af1-6baee2821fb3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_Depreciation"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentAbstract_0b83043b-0ea7-4eaf-8b99-46140e5e8e34" xlink:to="loc_us-gaap_Depreciation_a63482d0-52bf-4bda-8af1-6baee2821fb3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/PrepaidExpensesandOtherCurrentAssets" xlink:type="simple" xlink:href="plrx-20220630.xsd#PrepaidExpensesandOtherCurrentAssets"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/PrepaidExpensesandOtherCurrentAssets" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_236252bf-cba4-4a8c-9f7c-fbd8f008ed3b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_PrepaidExpensesAndOtherCurrentAssetsTextBlock_e90ac13d-6abe-4fec-8e0d-184c0b4e34ed" xlink:href="plrx-20220630.xsd#plrx_PrepaidExpensesAndOtherCurrentAssetsTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_236252bf-cba4-4a8c-9f7c-fbd8f008ed3b" xlink:to="loc_plrx_PrepaidExpensesAndOtherCurrentAssetsTextBlock_e90ac13d-6abe-4fec-8e0d-184c0b4e34ed" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/PrepaidExpensesandOtherCurrentAssetsTables" xlink:type="simple" xlink:href="plrx-20220630.xsd#PrepaidExpensesandOtherCurrentAssetsTables"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/PrepaidExpensesandOtherCurrentAssetsTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_3d4dea80-031f-4739-83fc-9d644f7f1f1d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_ScheduleOfPrepaidExpensesAndOtherCurrentAssetsTableTextBlock_6876aaa8-49d3-4d8c-9872-34b5af108959" xlink:href="plrx-20220630.xsd#plrx_ScheduleOfPrepaidExpensesAndOtherCurrentAssetsTableTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_3d4dea80-031f-4739-83fc-9d644f7f1f1d" xlink:to="loc_plrx_ScheduleOfPrepaidExpensesAndOtherCurrentAssetsTableTextBlock_6876aaa8-49d3-4d8c-9872-34b5af108959" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/PrepaidExpensesandOtherCurrentAssetsDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#PrepaidExpensesandOtherCurrentAssetsDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/PrepaidExpensesandOtherCurrentAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_9de67a6a-e90c-49c4-99af-9487a2ea85df" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_PrepaidResearchAndDevelopmentCurrent_738626d5-4ef3-494b-a783-1e26f7c6d47d" xlink:href="plrx-20220630.xsd#plrx_PrepaidResearchAndDevelopmentCurrent"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_9de67a6a-e90c-49c4-99af-9487a2ea85df" xlink:to="loc_plrx_PrepaidResearchAndDevelopmentCurrent_738626d5-4ef3-494b-a783-1e26f7c6d47d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidInsurance_267c699f-1a73-41f1-811d-77185ca3cf86" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PrepaidInsurance"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_9de67a6a-e90c-49c4-99af-9487a2ea85df" xlink:to="loc_us-gaap_PrepaidInsurance_267c699f-1a73-41f1-811d-77185ca3cf86" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_PrepaidLicensesCurrent_0a001cf8-4558-4c4e-87ba-426fc561b9da" xlink:href="plrx-20220630.xsd#plrx_PrepaidLicensesCurrent"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_9de67a6a-e90c-49c4-99af-9487a2ea85df" xlink:to="loc_plrx_PrepaidLicensesCurrent_0a001cf8-4558-4c4e-87ba-426fc561b9da" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestReceivableCurrent_a71735c6-8ac3-406a-a6b9-5935321aeae9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InterestReceivableCurrent"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_9de67a6a-e90c-49c4-99af-9487a2ea85df" xlink:to="loc_us-gaap_InterestReceivableCurrent_a71735c6-8ac3-406a-a6b9-5935321aeae9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherPrepaidExpenseCurrent_d58a1b09-4822-4686-b615-dc37dc35f75b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherPrepaidExpenseCurrent"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_9de67a6a-e90c-49c4-99af-9487a2ea85df" xlink:to="loc_us-gaap_OtherPrepaidExpenseCurrent_d58a1b09-4822-4686-b615-dc37dc35f75b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_e6b78b1d-4ef1-47c2-9148-ffb40d8c7e36" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DeferredCostsCapitalizedPrepaidAndOtherAssetsDisclosureAbstract_9de67a6a-e90c-49c4-99af-9487a2ea85df" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent_e6b78b1d-4ef1-47c2-9148-ffb40d8c7e36" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/AccruedLiabilitiesandOtherLongTermLiabilities" xlink:type="simple" xlink:href="plrx-20220630.xsd#AccruedLiabilitiesandOtherLongTermLiabilities"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/AccruedLiabilitiesandOtherLongTermLiabilities" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesAndOtherLiabilitiesAbstract_68cd99ac-3b3f-418e-b58b-126be3f801c0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccruedLiabilitiesAndOtherLiabilitiesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock_98cdae0e-709c-4b4d-a2a2-6cfe7d763ded" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccruedLiabilitiesAndOtherLiabilitiesAbstract_68cd99ac-3b3f-418e-b58b-126be3f801c0" xlink:to="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesDisclosureTextBlock_98cdae0e-709c-4b4d-a2a2-6cfe7d763ded" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/AccruedLiabilitiesandOtherLongTermLiabilitiesTables" xlink:type="simple" xlink:href="plrx-20220630.xsd#AccruedLiabilitiesandOtherLongTermLiabilitiesTables"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/AccruedLiabilitiesandOtherLongTermLiabilitiesTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesAndOtherLiabilitiesAbstract_fc82fd90-a23a-4282-8ddf-ec1bfe5a0599" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccruedLiabilitiesAndOtherLiabilitiesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock_9a5d98ec-2340-4bed-8efb-88ec38ab163a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccruedLiabilitiesAndOtherLiabilitiesAbstract_fc82fd90-a23a-4282-8ddf-ec1bfe5a0599" xlink:to="loc_us-gaap_ScheduleOfAccruedLiabilitiesTableTextBlock_9a5d98ec-2340-4bed-8efb-88ec38ab163a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/AccruedLiabilitiesandOtherLongTermLiabilitiesSummaryofAccruedLiabilitiesDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#AccruedLiabilitiesandOtherLongTermLiabilitiesSummaryofAccruedLiabilitiesDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/AccruedLiabilitiesandOtherLongTermLiabilitiesSummaryofAccruedLiabilitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesAndOtherLiabilitiesAbstract_bb9c0d67-fd6c-4366-8786-13e98a082e0c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccruedLiabilitiesAndOtherLiabilitiesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_470549b3-da38-4bc0-9bdf-b14f14a0c2c9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeRelatedLiabilitiesCurrent"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccruedLiabilitiesAndOtherLiabilitiesAbstract_bb9c0d67-fd6c-4366-8786-13e98a082e0c" xlink:to="loc_us-gaap_EmployeeRelatedLiabilitiesCurrent_470549b3-da38-4bc0-9bdf-b14f14a0c2c9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_AccruedResearchAndDevelopmentExpensesCurrent_a6595b22-a8ea-47f1-956d-fe68e17862d6" xlink:href="plrx-20220630.xsd#plrx_AccruedResearchAndDevelopmentExpensesCurrent"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccruedLiabilitiesAndOtherLiabilitiesAbstract_bb9c0d67-fd6c-4366-8786-13e98a082e0c" xlink:to="loc_plrx_AccruedResearchAndDevelopmentExpensesCurrent_a6595b22-a8ea-47f1-956d-fe68e17862d6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_320197e6-3752-4ffb-8f78-4cbd7824d4a4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccruedLiabilitiesAndOtherLiabilitiesAbstract_bb9c0d67-fd6c-4366-8786-13e98a082e0c" xlink:to="loc_us-gaap_AccountsPayableAndOtherAccruedLiabilitiesCurrent_320197e6-3752-4ffb-8f78-4cbd7824d4a4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent_15dbb3c8-b541-45d1-8d2e-de9a4b2f5974" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AccruedLiabilitiesAndOtherLiabilitiesAbstract_bb9c0d67-fd6c-4366-8786-13e98a082e0c" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent_15dbb3c8-b541-45d1-8d2e-de9a4b2f5974" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/Debt" xlink:type="simple" xlink:href="plrx-20220630.xsd#Debt"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/Debt" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureAbstract_9c99cb37-e484-4e96-bbb1-771353a8de94" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureTextBlock_dcf03d9a-e383-45c6-8607-406512b95aca" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtDisclosureTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_9c99cb37-e484-4e96-bbb1-771353a8de94" xlink:to="loc_us-gaap_DebtDisclosureTextBlock_dcf03d9a-e383-45c6-8607-406512b95aca" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/DebtTables" xlink:type="simple" xlink:href="plrx-20220630.xsd#DebtTables"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/DebtTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureAbstract_b2279d17-2d95-4f20-9099-991cee9bd916" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_9594e295-243a-4d35-b75f-d194a31daabf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_b2279d17-2d95-4f20-9099-991cee9bd916" xlink:to="loc_us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock_9594e295-243a-4d35-b75f-d194a31daabf" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/DebtNarrativeDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#DebtNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/DebtNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureAbstract_a7677f01-78ed-4a71-9465-8a14cf9dd86f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_48bace2d-f70f-4918-87f2-e33fba1c49ff" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_a7677f01-78ed-4a71-9465-8a14cf9dd86f" xlink:to="loc_us-gaap_DebtInstrumentTable_48bace2d-f70f-4918-87f2-e33fba1c49ff" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_a16ac11e-2815-4e0b-ac76-d5cd8c290885" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentTable_48bace2d-f70f-4918-87f2-e33fba1c49ff" xlink:to="loc_us-gaap_DebtInstrumentAxis_a16ac11e-2815-4e0b-ac76-d5cd8c290885" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_668a9140-8cb5-46e4-a557-62c80264f971" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentAxis_a16ac11e-2815-4e0b-ac76-d5cd8c290885" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_668a9140-8cb5-46e4-a557-62c80264f971" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_LoanAgreementMember_368489c5-9763-477f-94e9-d077d9d05e46" xlink:href="plrx-20220630.xsd#plrx_LoanAgreementMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_668a9140-8cb5-46e4-a557-62c80264f971" xlink:to="loc_plrx_LoanAgreementMember_368489c5-9763-477f-94e9-d077d9d05e46" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_f2a063f1-9046-4f63-a491-841ab9f97e42" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentTable_48bace2d-f70f-4918-87f2-e33fba1c49ff" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_f2a063f1-9046-4f63-a491-841ab9f97e42" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_79ae7170-ef78-44cc-9eae-12da3db55d73" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_f2a063f1-9046-4f63-a491-841ab9f97e42" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_79ae7170-ef78-44cc-9eae-12da3db55d73" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_TermLoanFacilityMember_83ffe3c9-44f7-4a39-8f3e-4b0c47831abf" xlink:href="plrx-20220630.xsd#plrx_TermLoanFacilityMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_79ae7170-ef78-44cc-9eae-12da3db55d73" xlink:to="loc_plrx_TermLoanFacilityMember_83ffe3c9-44f7-4a39-8f3e-4b0c47831abf" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_DebtDrawPeriodAxis_9d39e063-ea07-4c16-8bc2-ff045c71e442" xlink:href="plrx-20220630.xsd#plrx_DebtDrawPeriodAxis"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentTable_48bace2d-f70f-4918-87f2-e33fba1c49ff" xlink:to="loc_plrx_DebtDrawPeriodAxis_9d39e063-ea07-4c16-8bc2-ff045c71e442" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_DebtDrawPeriodDomain_202a1479-c47b-44c9-83e0-c9eb2b4ece0a" xlink:href="plrx-20220630.xsd#plrx_DebtDrawPeriodDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_plrx_DebtDrawPeriodAxis_9d39e063-ea07-4c16-8bc2-ff045c71e442" xlink:to="loc_plrx_DebtDrawPeriodDomain_202a1479-c47b-44c9-83e0-c9eb2b4ece0a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_DebtDrawTrancheOneMember_b521571c-5643-4749-ac16-b9c6f6531d2d" xlink:href="plrx-20220630.xsd#plrx_DebtDrawTrancheOneMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_plrx_DebtDrawPeriodDomain_202a1479-c47b-44c9-83e0-c9eb2b4ece0a" xlink:to="loc_plrx_DebtDrawTrancheOneMember_b521571c-5643-4749-ac16-b9c6f6531d2d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_DebtDrawTrancheTwoMember_932ee4f6-f148-4fe8-ac47-ac51afa14aa0" xlink:href="plrx-20220630.xsd#plrx_DebtDrawTrancheTwoMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_plrx_DebtDrawPeriodDomain_202a1479-c47b-44c9-83e0-c9eb2b4ece0a" xlink:to="loc_plrx_DebtDrawTrancheTwoMember_932ee4f6-f148-4fe8-ac47-ac51afa14aa0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_DebtDrawTrancheThreeMember_92991838-de3c-4516-9f01-80e39aff888a" xlink:href="plrx-20220630.xsd#plrx_DebtDrawTrancheThreeMember"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_plrx_DebtDrawPeriodDomain_202a1479-c47b-44c9-83e0-c9eb2b4ece0a" xlink:to="loc_plrx_DebtDrawTrancheThreeMember_92991838-de3c-4516-9f01-80e39aff888a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_ffb610f1-aebb-4567-b42b-dd1a0a2993fc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateAxis"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentTable_48bace2d-f70f-4918-87f2-e33fba1c49ff" xlink:to="loc_us-gaap_VariableRateAxis_ffb610f1-aebb-4567-b42b-dd1a0a2993fc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_5e5b0c60-d29f-42fe-9481-06d3d628c6c4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableRateDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_VariableRateAxis_ffb610f1-aebb-4567-b42b-dd1a0a2993fc" xlink:to="loc_us-gaap_VariableRateDomain_5e5b0c60-d29f-42fe-9481-06d3d628c6c4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_57730a00-cac0-4392-afdd-f5f3d6f50d43" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_VariableRateDomain_5e5b0c60-d29f-42fe-9481-06d3d628c6c4" xlink:to="loc_us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember_57730a00-cac0-4392-afdd-f5f3d6f50d43" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_54ea0e2a-66c5-4ab9-9b08-3f32bfc59f2e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentTable_48bace2d-f70f-4918-87f2-e33fba1c49ff" xlink:to="loc_us-gaap_DebtInstrumentLineItems_54ea0e2a-66c5-4ab9-9b08-3f32bfc59f2e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_f5a15852-f18e-4f0d-9b8c-56abeff71c5b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_54ea0e2a-66c5-4ab9-9b08-3f32bfc59f2e" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_f5a15852-f18e-4f0d-9b8c-56abeff71c5b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfDebt_acb62af8-ddef-4865-b913-b029d51afbe3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ProceedsFromIssuanceOfDebt"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_54ea0e2a-66c5-4ab9-9b08-3f32bfc59f2e" xlink:to="loc_us-gaap_ProceedsFromIssuanceOfDebt_acb62af8-ddef-4865-b913-b029d51afbe3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_DebtInstrumentTrancheOneAmountUndrawn_c09544fe-448f-4987-a527-bd1a4487beff" xlink:href="plrx-20220630.xsd#plrx_DebtInstrumentTrancheOneAmountUndrawn"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_54ea0e2a-66c5-4ab9-9b08-3f32bfc59f2e" xlink:to="loc_plrx_DebtInstrumentTrancheOneAmountUndrawn_c09544fe-448f-4987-a527-bd1a4487beff" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_DebtInstrumentAmountAvailableAfterTrancheOne_fd02df5a-f55f-4f83-aa47-5cc2edf56972" xlink:href="plrx-20220630.xsd#plrx_DebtInstrumentAmountAvailableAfterTrancheOne"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_54ea0e2a-66c5-4ab9-9b08-3f32bfc59f2e" xlink:to="loc_plrx_DebtInstrumentAmountAvailableAfterTrancheOne_fd02df5a-f55f-4f83-aa47-5cc2edf56972" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_DebtInstrumentNumberOfTranches_a88a37a5-7240-4d54-8def-dd7498876fc1" xlink:href="plrx-20220630.xsd#plrx_DebtInstrumentNumberOfTranches"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_54ea0e2a-66c5-4ab9-9b08-3f32bfc59f2e" xlink:to="loc_plrx_DebtInstrumentNumberOfTranches_a88a37a5-7240-4d54-8def-dd7498876fc1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_00366bb3-8799-43b0-b0fe-60fd27d3233a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_54ea0e2a-66c5-4ab9-9b08-3f32bfc59f2e" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_00366bb3-8799-43b0-b0fe-60fd27d3233a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_5461d962-b1e0-4771-9fa7-7d457f12f0c8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_54ea0e2a-66c5-4ab9-9b08-3f32bfc59f2e" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_5461d962-b1e0-4771-9fa7-7d457f12f0c8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpense_6dfa0fdd-a725-49d3-bb4b-3e9501f65e75" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_InterestExpense"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_54ea0e2a-66c5-4ab9-9b08-3f32bfc59f2e" xlink:to="loc_us-gaap_InterestExpense_6dfa0fdd-a725-49d3-bb4b-3e9501f65e75" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_f22d1c2d-6975-48fd-83e9-6574c294d2d1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:presentationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtInstrumentLineItems_54ea0e2a-66c5-4ab9-9b08-3f32bfc59f2e" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_f22d1c2d-6975-48fd-83e9-6574c294d2d1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/DebtScheduleofMaturitiesofLongTermDebtDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#DebtScheduleofMaturitiesofLongTermDebtDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/DebtScheduleofMaturitiesofLongTermDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtDisclosureAbstract_c554a7b5-65f5-45ac-bbd2-e2ee74fc2953" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_07ec75a7-0885-4ba4-a081-959b883e8633" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_c554a7b5-65f5-45ac-bbd2-e2ee74fc2953" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear_07ec75a7-0885-4ba4-a081-959b883e8633" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_55f08b65-99d1-4899-a18b-6dc246b67e3c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_c554a7b5-65f5-45ac-bbd2-e2ee74fc2953" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_55f08b65-99d1-4899-a18b-6dc246b67e3c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_5b7fa379-a340-4aac-9ebf-3d42bd392031" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_c554a7b5-65f5-45ac-bbd2-e2ee74fc2953" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_5b7fa379-a340-4aac-9ebf-3d42bd392031" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_fd2ce65f-b0dc-4a7f-8f71-b3b08477d540" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_c554a7b5-65f5-45ac-bbd2-e2ee74fc2953" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree_fd2ce65f-b0dc-4a7f-8f71-b3b08477d540" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_250d53e4-1672-467e-8846-ff97b8f3e0e3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_c554a7b5-65f5-45ac-bbd2-e2ee74fc2953" xlink:to="loc_us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour_250d53e4-1672-467e-8846-ff97b8f3e0e3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_LongTermDebtMaturityAfterYearFour_3ed34047-601b-4bf0-b4bb-a679bb48d380" xlink:href="plrx-20220630.xsd#plrx_LongTermDebtMaturityAfterYearFour"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_c554a7b5-65f5-45ac-bbd2-e2ee74fc2953" xlink:to="loc_plrx_LongTermDebtMaturityAfterYearFour_3ed34047-601b-4bf0-b4bb-a679bb48d380" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_3dbb8d63-4511-4fb7-8f3a-b2d83c552f45" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DebtDisclosureAbstract_c554a7b5-65f5-45ac-bbd2-e2ee74fc2953" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_3dbb8d63-4511-4fb7-8f3a-b2d83c552f45" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/NovartisCollaborationandLicenseAgreementtheNovartisAgreement" xlink:type="simple" xlink:href="plrx-20220630.xsd#NovartisCollaborationandLicenseAgreementtheNovartisAgreement"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/NovartisCollaborationandLicenseAgreementtheNovartisAgreement" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_37cc0462-7e42-4bbb-b9e6-93f73d536ef2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollaborativeArrangementDisclosureTextBlock_7eee8f4d-101c-4de4-adaa-ae308de48d9a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CollaborativeArrangementDisclosureTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_37cc0462-7e42-4bbb-b9e6-93f73d536ef2" xlink:to="loc_us-gaap_CollaborativeArrangementDisclosureTextBlock_7eee8f4d-101c-4de4-adaa-ae308de48d9a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/NovartisCollaborationandLicenseAgreementtheNovartisAgreementNarrativeDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#NovartisCollaborationandLicenseAgreementtheNovartisAgreementNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/NovartisCollaborationandLicenseAgreementtheNovartisAgreementNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_3eae5623-fa0d-4a05-b679-95e7296f6261" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_2735456f-39ff-40f5-bcb7-05d66dadf836" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_3eae5623-fa0d-4a05-b679-95e7296f6261" xlink:to="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_2735456f-39ff-40f5-bcb7-05d66dadf836" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_d7237b03-5d03-44fc-8a36-1a057a39b124" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_2735456f-39ff-40f5-bcb7-05d66dadf836" xlink:to="loc_srt_RangeAxis_d7237b03-5d03-44fc-8a36-1a057a39b124" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_2e6a1554-4013-4c4b-9e24-c6231a34752f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeAxis_d7237b03-5d03-44fc-8a36-1a057a39b124" xlink:to="loc_srt_RangeMember_2e6a1554-4013-4c4b-9e24-c6231a34752f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_3c20d538-7262-4691-871b-642e3a059ce6" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeMember_2e6a1554-4013-4c4b-9e24-c6231a34752f" xlink:to="loc_srt_MaximumMember_3c20d538-7262-4691-871b-642e3a059ce6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5bcc76c5-3506-49a4-b12c-c1c8bf2615a2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_2735456f-39ff-40f5-bcb7-05d66dadf836" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5bcc76c5-3506-49a4-b12c-c1c8bf2615a2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_5101733c-5a1b-431e-a284-86e6aa6ea12e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_5bcc76c5-3506-49a4-b12c-c1c8bf2615a2" xlink:to="loc_us-gaap_RelatedPartyDomain_5101733c-5a1b-431e-a284-86e6aa6ea12e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_NovartisMember_39204542-a87a-4a5d-ac2a-790d621ce402" xlink:href="plrx-20220630.xsd#plrx_NovartisMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RelatedPartyDomain_5101733c-5a1b-431e-a284-86e6aa6ea12e" xlink:to="loc_plrx_NovartisMember_39204542-a87a-4a5d-ac2a-790d621ce402" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_84a463af-0921-4f9d-8c26-2e80900254dc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_2735456f-39ff-40f5-bcb7-05d66dadf836" xlink:to="loc_us-gaap_TypeOfArrangementAxis_84a463af-0921-4f9d-8c26-2e80900254dc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f5b5b012-e694-468f-9df0-90e011e5b26a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TypeOfArrangementAxis_84a463af-0921-4f9d-8c26-2e80900254dc" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f5b5b012-e694-468f-9df0-90e011e5b26a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_NovartisAgreementMember_b9b82eb8-81da-4b8f-ac8c-ed79c2258b63" xlink:href="plrx-20220630.xsd#plrx_NovartisAgreementMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f5b5b012-e694-468f-9df0-90e011e5b26a" xlink:to="loc_plrx_NovartisAgreementMember_b9b82eb8-81da-4b8f-ac8c-ed79c2258b63" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_NovartisAgreementRDForPLN1474Member_2ea7477d-7824-4656-b31c-791432cd9d46" xlink:href="plrx-20220630.xsd#plrx_NovartisAgreementRDForPLN1474Member"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f5b5b012-e694-468f-9df0-90e011e5b26a" xlink:to="loc_plrx_NovartisAgreementRDForPLN1474Member_2ea7477d-7824-4656-b31c-791432cd9d46" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_NovartisAgreementRDForIntegrinResearchTargetsMember_25dc8fb8-e0fe-4cdc-b010-885957cdaf63" xlink:href="plrx-20220630.xsd#plrx_NovartisAgreementRDForIntegrinResearchTargetsMember"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_f5b5b012-e694-468f-9df0-90e011e5b26a" xlink:to="loc_plrx_NovartisAgreementRDForIntegrinResearchTargetsMember_25dc8fb8-e0fe-4cdc-b010-885957cdaf63" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_b446e351-9179-4793-adb8-765b8c45450a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_2735456f-39ff-40f5-bcb7-05d66dadf836" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_b446e351-9179-4793-adb8-765b8c45450a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_71bea67b-635a-427b-b4bc-ef709208ead3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_b446e351-9179-4793-adb8-765b8c45450a" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_71bea67b-635a-427b-b4bc-ef709208ead3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_8431540d-f4e4-436f-bf14-c3ca7c4e0e48" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentExpenseMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_71bea67b-635a-427b-b4bc-ef709208ead3" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_8431540d-f4e4-436f-bf14-c3ca7c4e0e48" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_2a8482ea-8974-42b0-bdbe-eeec56a591c5" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_2735456f-39ff-40f5-bcb7-05d66dadf836" xlink:to="loc_srt_ProductOrServiceAxis_2a8482ea-8974-42b0-bdbe-eeec56a591c5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_c67377bd-d9f2-4456-b4c9-613589ab7374" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_ProductOrServiceAxis_2a8482ea-8974-42b0-bdbe-eeec56a591c5" xlink:to="loc_srt_ProductsAndServicesDomain_c67377bd-d9f2-4456-b4c9-613589ab7374" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_AchievementOfFirstPatientDosingMilestoneMember_49de8f43-50d3-4688-a3cb-00c3d43c0746" xlink:href="plrx-20220630.xsd#plrx_AchievementOfFirstPatientDosingMilestoneMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_ProductsAndServicesDomain_c67377bd-d9f2-4456-b4c9-613589ab7374" xlink:to="loc_plrx_AchievementOfFirstPatientDosingMilestoneMember_49de8f43-50d3-4688-a3cb-00c3d43c0746" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_f4c02d9f-3ef9-410c-9715-4bb0c200be24" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfCollaborativeArrangementsAndNoncollaborativeArrangementTransactionsTable_2735456f-39ff-40f5-bcb7-05d66dadf836" xlink:to="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_f4c02d9f-3ef9-410c-9715-4bb0c200be24" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_NumberOfIntegrinResearchTargets_fee7e389-d142-426b-94da-eb9ff28e52b6" xlink:href="plrx-20220630.xsd#plrx_NumberOfIntegrinResearchTargets"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_f4c02d9f-3ef9-410c-9715-4bb0c200be24" xlink:to="loc_plrx_NumberOfIntegrinResearchTargets_fee7e389-d142-426b-94da-eb9ff28e52b6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_ProceedsFromUpfrontNonRefundableLicenseFee_79ad0054-c0f9-4124-b9c7-b58eeb1b1801" xlink:href="plrx-20220630.xsd#plrx_ProceedsFromUpfrontNonRefundableLicenseFee"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_f4c02d9f-3ef9-410c-9715-4bb0c200be24" xlink:to="loc_plrx_ProceedsFromUpfrontNonRefundableLicenseFee_79ad0054-c0f9-4124-b9c7-b58eeb1b1801" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_CollaborationAndLicenseAgreementIntegrinResearchTargetsAmount_58cfe78c-00d0-4f10-b5e3-4f0da68ad2b6" xlink:href="plrx-20220630.xsd#plrx_CollaborationAndLicenseAgreementIntegrinResearchTargetsAmount"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_f4c02d9f-3ef9-410c-9715-4bb0c200be24" xlink:to="loc_plrx_CollaborationAndLicenseAgreementIntegrinResearchTargetsAmount_58cfe78c-00d0-4f10-b5e3-4f0da68ad2b6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_aa08f104-2bf1-439b-beda-a3508029d218" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionAmountsOfTransaction"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_f4c02d9f-3ef9-410c-9715-4bb0c200be24" xlink:to="loc_us-gaap_RelatedPartyTransactionAmountsOfTransaction_aa08f104-2bf1-439b-beda-a3508029d218" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DueFromRelatedParties_075f3462-1487-4497-80c5-91bf115fa778" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DueFromRelatedParties"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_f4c02d9f-3ef9-410c-9715-4bb0c200be24" xlink:to="loc_us-gaap_DueFromRelatedParties_075f3462-1487-4497-80c5-91bf115fa778" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromRelatedParties_63c54618-9fa1-4c38-8f5c-e77a5d07bc8c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueFromRelatedParties"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_f4c02d9f-3ef9-410c-9715-4bb0c200be24" xlink:to="loc_us-gaap_RevenueFromRelatedParties_63c54618-9fa1-4c38-8f5c-e77a5d07bc8c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_CollaborationAndLicenseAgreementIntegrinResearchTargetsAmountRemaining_28fe0e5c-2d0d-42ff-ab58-28261a8d229d" xlink:href="plrx-20220630.xsd#plrx_CollaborationAndLicenseAgreementIntegrinResearchTargetsAmountRemaining"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems_f4c02d9f-3ef9-410c-9715-4bb0c200be24" xlink:to="loc_plrx_CollaborationAndLicenseAgreementIntegrinResearchTargetsAmountRemaining_28fe0e5c-2d0d-42ff-ab58-28261a8d229d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/NovartisCollaborationandLicenseAgreementtheNovartisAgreementPerformanceObligationDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#NovartisCollaborationandLicenseAgreementtheNovartisAgreementPerformanceObligationDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/NovartisCollaborationandLicenseAgreementtheNovartisAgreementPerformanceObligationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_a25c0198-d27a-4cc9-adaf-9a5cb1ab10ba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_f43864e7-b831-43d5-9882-d947b5f99b85" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_a25c0198-d27a-4cc9-adaf-9a5cb1ab10ba" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_f43864e7-b831-43d5-9882-d947b5f99b85" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_feb0cd7c-782a-4aa6-9a4c-65d603855454" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_f43864e7-b831-43d5-9882-d947b5f99b85" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_feb0cd7c-782a-4aa6-9a4c-65d603855454" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_9694b379-48d6-4163-a9a8-41db3a3c43d1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_feb0cd7c-782a-4aa6-9a4c-65d603855454" xlink:to="loc_us-gaap_RelatedPartyDomain_9694b379-48d6-4163-a9a8-41db3a3c43d1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_NovartisMember_7cc27819-6caf-4989-93e9-63cee1e667f6" xlink:href="plrx-20220630.xsd#plrx_NovartisMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RelatedPartyDomain_9694b379-48d6-4163-a9a8-41db3a3c43d1" xlink:to="loc_plrx_NovartisMember_7cc27819-6caf-4989-93e9-63cee1e667f6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfArrangementAxis_224e801e-4994-49f6-91d2-c3bbf629ed13" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TypeOfArrangementAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_f43864e7-b831-43d5-9882-d947b5f99b85" xlink:to="loc_us-gaap_TypeOfArrangementAxis_224e801e-4994-49f6-91d2-c3bbf629ed13" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_c9f047bd-95a2-4ef8-ba9f-4b93fe8ddf0a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ArrangementsAndNonarrangementTransactionsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TypeOfArrangementAxis_224e801e-4994-49f6-91d2-c3bbf629ed13" xlink:to="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_c9f047bd-95a2-4ef8-ba9f-4b93fe8ddf0a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_NovartisAgreementRDForIntegrinResearchTargetsMember_62800548-653a-4dda-82a4-d9800ce82fe2" xlink:href="plrx-20220630.xsd#plrx_NovartisAgreementRDForIntegrinResearchTargetsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ArrangementsAndNonarrangementTransactionsMember_c9f047bd-95a2-4ef8-ba9f-4b93fe8ddf0a" xlink:to="loc_plrx_NovartisAgreementRDForIntegrinResearchTargetsMember_62800548-653a-4dda-82a4-d9800ce82fe2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_4c7e834d-3d20-4d9d-802a-69c475e15d4e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_f43864e7-b831-43d5-9882-d947b5f99b85" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_4c7e834d-3d20-4d9d-802a-69c475e15d4e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_e74650df-91d7-475d-b626-0c975b3f6af4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_f43864e7-b831-43d5-9882-d947b5f99b85" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_e74650df-91d7-475d-b626-0c975b3f6af4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_e0d81fd9-72c9-4888-b850-9f8d99e41524" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_e74650df-91d7-475d-b626-0c975b3f6af4" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_e0d81fd9-72c9-4888-b850-9f8d99e41524" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_7f489bd0-326c-46a7-bf20-ff5fc109f237" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_e74650df-91d7-475d-b626-0c975b3f6af4" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_7f489bd0-326c-46a7-bf20-ff5fc109f237" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/NovartisCollaborationandLicenseAgreementtheNovartisAgreementPerformanceObligationDetails_1" xlink:type="simple" xlink:href="plrx-20220630.xsd#NovartisCollaborationandLicenseAgreementtheNovartisAgreementPerformanceObligationDetails_1"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/NovartisCollaborationandLicenseAgreementtheNovartisAgreementPerformanceObligationDetails_1" xlink:type="extended"/>
  <link:roleRef roleURI="http://www.pliantrx.com/role/RegentoftheUniversityofCaliforniaLicenseAgreementtheUCAgreement" xlink:type="simple" xlink:href="plrx-20220630.xsd#RegentoftheUniversityofCaliforniaLicenseAgreementtheUCAgreement"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/RegentoftheUniversityofCaliforniaLicenseAgreementtheUCAgreement" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_plrx_LicenseAgreementsAbstract_e6415860-67b8-4769-921b-72e709282f55" xlink:href="plrx-20220630.xsd#plrx_LicenseAgreementsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_LicenseAgreementsTextBlock_a30129cf-70c2-454e-ab55-af597d206461" xlink:href="plrx-20220630.xsd#plrx_LicenseAgreementsTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_plrx_LicenseAgreementsAbstract_e6415860-67b8-4769-921b-72e709282f55" xlink:to="loc_plrx_LicenseAgreementsTextBlock_a30129cf-70c2-454e-ab55-af597d206461" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/RegentoftheUniversityofCaliforniaLicenseAgreementtheUCAgreementDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#RegentoftheUniversityofCaliforniaLicenseAgreementtheUCAgreementDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/RegentoftheUniversityofCaliforniaLicenseAgreementtheUCAgreementDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_plrx_LicenseAgreementsAbstract_294d6895-eb2d-4cad-9c9c-58be26056782" xlink:href="plrx-20220630.xsd#plrx_LicenseAgreementsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_LicenseAgreementsTable_6dc91972-a16a-40ab-a09e-22ec87bf64f2" xlink:href="plrx-20220630.xsd#plrx_LicenseAgreementsTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_plrx_LicenseAgreementsAbstract_294d6895-eb2d-4cad-9c9c-58be26056782" xlink:to="loc_plrx_LicenseAgreementsTable_6dc91972-a16a-40ab-a09e-22ec87bf64f2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_ad8519b8-5e66-4d4c-8fdf-d12d3bed81bf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_plrx_LicenseAgreementsTable_6dc91972-a16a-40ab-a09e-22ec87bf64f2" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_ad8519b8-5e66-4d4c-8fdf-d12d3bed81bf" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_d20b8624-17b9-4db6-869a-b41bdc73b462" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_ad8519b8-5e66-4d4c-8fdf-d12d3bed81bf" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_d20b8624-17b9-4db6-869a-b41bdc73b462" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LicensingAgreementsMember_13d75c0f-3202-4b78-ab5c-94de78321cd2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LicensingAgreementsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_d20b8624-17b9-4db6-869a-b41bdc73b462" xlink:to="loc_us-gaap_LicensingAgreementsMember_13d75c0f-3202-4b78-ab5c-94de78321cd2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_1db1ccad-5c88-4f43-8a2a-0abcda91cebd" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductOrServiceAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_plrx_LicenseAgreementsTable_6dc91972-a16a-40ab-a09e-22ec87bf64f2" xlink:to="loc_srt_ProductOrServiceAxis_1db1ccad-5c88-4f43-8a2a-0abcda91cebd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_f4e9e96a-fd6e-4615-b4b2-268a4d63d6d4" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_ProductsAndServicesDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_ProductOrServiceAxis_1db1ccad-5c88-4f43-8a2a-0abcda91cebd" xlink:to="loc_srt_ProductsAndServicesDomain_f4e9e96a-fd6e-4615-b4b2-268a4d63d6d4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_UCRegentsMember_33c1e5a3-ed87-494e-a073-99ec53cc3517" xlink:href="plrx-20220630.xsd#plrx_UCRegentsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_ProductsAndServicesDomain_f4e9e96a-fd6e-4615-b4b2-268a4d63d6d4" xlink:to="loc_plrx_UCRegentsMember_33c1e5a3-ed87-494e-a073-99ec53cc3517" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_LicenseAgreementsLineItems_f1257af7-0186-4f52-8583-8a7a2df12292" xlink:href="plrx-20220630.xsd#plrx_LicenseAgreementsLineItems"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_plrx_LicenseAgreementsTable_6dc91972-a16a-40ab-a09e-22ec87bf64f2" xlink:to="loc_plrx_LicenseAgreementsLineItems_f1257af7-0186-4f52-8583-8a7a2df12292" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_MilestoneAndAnnualRoyaltyPaid_5688f953-cbb0-4f79-87f0-6dc597866d68" xlink:href="plrx-20220630.xsd#plrx_MilestoneAndAnnualRoyaltyPaid"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_plrx_LicenseAgreementsLineItems_f1257af7-0186-4f52-8583-8a7a2df12292" xlink:to="loc_plrx_MilestoneAndAnnualRoyaltyPaid_5688f953-cbb0-4f79-87f0-6dc597866d68" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/AdimabDevelopmentandOptionAgreementtheAdimabAgreement" xlink:type="simple" xlink:href="plrx-20220630.xsd#AdimabDevelopmentandOptionAgreementtheAdimabAgreement"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/AdimabDevelopmentandOptionAgreementtheAdimabAgreement" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentAbstract_c3b9a203-e8b2-4aa5-978f-56e43ea20855" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchDevelopmentAndComputerSoftwareDisclosureTextBlock_9d3d2037-cd79-48b8-ad26-0c76b1f19b91" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchDevelopmentAndComputerSoftwareDisclosureTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ResearchAndDevelopmentAbstract_c3b9a203-e8b2-4aa5-978f-56e43ea20855" xlink:to="loc_us-gaap_ResearchDevelopmentAndComputerSoftwareDisclosureTextBlock_9d3d2037-cd79-48b8-ad26-0c76b1f19b91" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/AdimabDevelopmentandOptionAgreementtheAdimabAgreementDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#AdimabDevelopmentandOptionAgreementtheAdimabAgreementDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/AdimabDevelopmentandOptionAgreementtheAdimabAgreementDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentAbstract_182fd541-dc24-48cc-807f-9854162799ab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfResearchAndDevelopmentArrangementContractToPerformForOthersTable_0bece293-a5d2-4275-9a3c-60fbb8911158" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfResearchAndDevelopmentArrangementContractToPerformForOthersTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ResearchAndDevelopmentAbstract_182fd541-dc24-48cc-807f-9854162799ab" xlink:to="loc_us-gaap_ScheduleOfResearchAndDevelopmentArrangementContractToPerformForOthersTable_0bece293-a5d2-4275-9a3c-60fbb8911158" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis_a4c92082-2462-4b79-8cc3-a0ecab126323" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfResearchAndDevelopmentArrangementContractToPerformForOthersTable_0bece293-a5d2-4275-9a3c-60fbb8911158" xlink:to="loc_us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis_a4c92082-2462-4b79-8cc3-a0ecab126323" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersTypeDomain_7c407053-caaf-48a8-a94a-b899e427d4d2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersTypeDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersByTypeAxis_a4c92082-2462-4b79-8cc3-a0ecab126323" xlink:to="loc_us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersTypeDomain_7c407053-caaf-48a8-a94a-b899e427d4d2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_AdimabAgreementMember_0643af0a-8156-41a4-ad37-33db3f88f90c" xlink:href="plrx-20220630.xsd#plrx_AdimabAgreementMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersTypeDomain_7c407053-caaf-48a8-a94a-b899e427d4d2" xlink:to="loc_plrx_AdimabAgreementMember_0643af0a-8156-41a4-ad37-33db3f88f90c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersLineItems_bc0bd258-bb7d-48e4-88e9-9ffc626e227c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfResearchAndDevelopmentArrangementContractToPerformForOthersTable_0bece293-a5d2-4275-9a3c-60fbb8911158" xlink:to="loc_us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersLineItems_bc0bd258-bb7d-48e4-88e9-9ffc626e227c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_36d994c1-b4e3-43b9-a89e-02f155506925" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ResearchAndDevelopmentArrangementContractToPerformForOthersLineItems_bc0bd258-bb7d-48e4-88e9-9ffc626e227c" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_36d994c1-b4e3-43b9-a89e-02f155506925" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/RedeemableConvertiblePreferredStock" xlink:type="simple" xlink:href="plrx-20220630.xsd#RedeemableConvertiblePreferredStock"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/RedeemableConvertiblePreferredStock" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityDisclosureAbstract_d1a8863d-6b48-45a7-a3f6-5912cd47f4fb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TemporaryEquityDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_RedeemableConvertiblePreferredStockTextBlock_f20f6cc9-c03e-428d-9738-edd40edaf01c" xlink:href="plrx-20220630.xsd#plrx_RedeemableConvertiblePreferredStockTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TemporaryEquityDisclosureAbstract_d1a8863d-6b48-45a7-a3f6-5912cd47f4fb" xlink:to="loc_plrx_RedeemableConvertiblePreferredStockTextBlock_f20f6cc9-c03e-428d-9738-edd40edaf01c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/RedeemableConvertiblePreferredStockDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#RedeemableConvertiblePreferredStockDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/RedeemableConvertiblePreferredStockDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityDisclosureAbstract_92c8d2a0-d6d0-44d2-9fcd-1916bbf3fbb9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TemporaryEquityDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityByClassOfStockTable_910b053d-0e8d-4177-8f85-8b7bb428f6a1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TemporaryEquityByClassOfStockTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TemporaryEquityDisclosureAbstract_92c8d2a0-d6d0-44d2-9fcd-1916bbf3fbb9" xlink:to="loc_us-gaap_TemporaryEquityByClassOfStockTable_910b053d-0e8d-4177-8f85-8b7bb428f6a1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementClassOfStockAxis_025e3a22-b744-4d6f-a4f9-37367537b6b6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StatementClassOfStockAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TemporaryEquityByClassOfStockTable_910b053d-0e8d-4177-8f85-8b7bb428f6a1" xlink:to="loc_us-gaap_StatementClassOfStockAxis_025e3a22-b744-4d6f-a4f9-37367537b6b6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockDomain_7df0c7b6-5cd7-439c-96ea-bdd88526b70b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ClassOfStockDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_StatementClassOfStockAxis_025e3a22-b744-4d6f-a4f9-37367537b6b6" xlink:to="loc_us-gaap_ClassOfStockDomain_7df0c7b6-5cd7-439c-96ea-bdd88526b70b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RedeemablePreferredStockMember_99aff619-dfc4-4406-8bc6-fb84cd5b9682" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RedeemablePreferredStockMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ClassOfStockDomain_7df0c7b6-5cd7-439c-96ea-bdd88526b70b" xlink:to="loc_us-gaap_RedeemablePreferredStockMember_99aff619-dfc4-4406-8bc6-fb84cd5b9682" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TemporaryEquityLineItems_1860b900-4fe2-4319-8ea2-462e6a1a671b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_TemporaryEquityLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TemporaryEquityByClassOfStockTable_910b053d-0e8d-4177-8f85-8b7bb428f6a1" xlink:to="loc_us-gaap_TemporaryEquityLineItems_1860b900-4fe2-4319-8ea2-462e6a1a671b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_NumberOfClassesOfStockAuthorized_43115d7b-e0ae-44f6-b334-2ccf203b99f2" xlink:href="plrx-20220630.xsd#plrx_NumberOfClassesOfStockAuthorized"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TemporaryEquityLineItems_1860b900-4fe2-4319-8ea2-462e6a1a671b" xlink:to="loc_plrx_NumberOfClassesOfStockAuthorized_43115d7b-e0ae-44f6-b334-2ccf203b99f2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesAuthorized_5727cd2d-335f-4f13-97ce-ddb586148deb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PreferredStockSharesAuthorized"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TemporaryEquityLineItems_1860b900-4fe2-4319-8ea2-462e6a1a671b" xlink:to="loc_us-gaap_PreferredStockSharesAuthorized_5727cd2d-335f-4f13-97ce-ddb586148deb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding_c03853cf-a94f-480d-a600-a9bddd8b580c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_TemporaryEquityLineItems_1860b900-4fe2-4319-8ea2-462e6a1a671b" xlink:to="loc_us-gaap_PreferredStockSharesOutstanding_c03853cf-a94f-480d-a600-a9bddd8b580c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/CommonStock" xlink:type="simple" xlink:href="plrx-20220630.xsd#CommonStock"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/CommonStock" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityAbstract_b14228f3-5840-400a-87a0-ce718e90f36c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquityNoteDisclosureTextBlock_69e54974-c37c-4c07-af2a-160d02781930" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockholdersEquityNoteDisclosureTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityAbstract_b14228f3-5840-400a-87a0-ce718e90f36c" xlink:to="loc_us-gaap_StockholdersEquityNoteDisclosureTextBlock_69e54974-c37c-4c07-af2a-160d02781930" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/CommonStockTables" xlink:type="simple" xlink:href="plrx-20220630.xsd#CommonStockTables"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/CommonStockTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityAbstract_dea9f604-c6fc-4a6e-af9d-3c619fac39d9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_ScheduleOfCommonStockReservedForFutureIssuanceTableTableTextBlock_96ebfb6b-ea8e-45e5-8ed9-8e3dbc39eeb4" xlink:href="plrx-20220630.xsd#plrx_ScheduleOfCommonStockReservedForFutureIssuanceTableTableTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityAbstract_dea9f604-c6fc-4a6e-af9d-3c619fac39d9" xlink:to="loc_plrx_ScheduleOfCommonStockReservedForFutureIssuanceTableTableTextBlock_96ebfb6b-ea8e-45e5-8ed9-8e3dbc39eeb4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/CommonStockNarrativeDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#CommonStockNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/CommonStockNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityAbstract_2907876a-2763-4791-b53f-b4b7aec2b5d0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_9ad787c1-ae87-4f23-9d2f-7d15b17f08a2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityAbstract_2907876a-2763-4791-b53f-b4b7aec2b5d0" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_9ad787c1-ae87-4f23-9d2f-7d15b17f08a2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockParOrStatedValuePerShare_ed681d3a-c269-4f00-a7a4-5cd95701d72c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockParOrStatedValuePerShare"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityAbstract_2907876a-2763-4791-b53f-b4b7aec2b5d0" xlink:to="loc_us-gaap_CommonStockParOrStatedValuePerShare_ed681d3a-c269-4f00-a7a4-5cd95701d72c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockVotingRights_e5cf233e-fcf5-4167-9657-b53403d74250" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockVotingRights"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityAbstract_2907876a-2763-4791-b53f-b4b7aec2b5d0" xlink:to="loc_us-gaap_CommonStockVotingRights_e5cf233e-fcf5-4167-9657-b53403d74250" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareDeclared_daec2fce-4175-42ce-9f06-3e278b221cbb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockDividendsPerShareDeclared"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityAbstract_2907876a-2763-4791-b53f-b4b7aec2b5d0" xlink:to="loc_us-gaap_CommonStockDividendsPerShareDeclared_daec2fce-4175-42ce-9f06-3e278b221cbb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockDividendsPerShareCashPaid_31e3c9f1-3886-4986-a00a-e8d3f4b06644" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockDividendsPerShareCashPaid"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityAbstract_2907876a-2763-4791-b53f-b4b7aec2b5d0" xlink:to="loc_us-gaap_CommonStockDividendsPerShareCashPaid_31e3c9f1-3886-4986-a00a-e8d3f4b06644" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/CommonStockScheduleofSharesReservedforFutureIssuanceDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#CommonStockScheduleofSharesReservedforFutureIssuanceDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/CommonStockScheduleofSharesReservedforFutureIssuanceDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityAbstract_786ddbea-0514-4ed4-95a4-c5f389c19a6b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EquityAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_53aadb01-3927-43c5-a06e-539333b7be67" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EquityAbstract_786ddbea-0514-4ed4-95a4-c5f389c19a6b" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_53aadb01-3927-43c5-a06e-539333b7be67" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_8e606fe2-7bbc-44d6-b36a-ab4f0391de14" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_53aadb01-3927-43c5-a06e-539333b7be67" xlink:to="loc_us-gaap_AwardTypeAxis_8e606fe2-7bbc-44d6-b36a-ab4f0391de14" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9383a066-12ee-43a0-affa-3c65036adac7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_8e606fe2-7bbc-44d6-b36a-ab4f0391de14" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9383a066-12ee-43a0-affa-3c65036adac7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_e590f51c-d640-4aa2-9c2b-438deec7b64b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9383a066-12ee-43a0-affa-3c65036adac7" xlink:to="loc_us-gaap_EmployeeStockOptionMember_e590f51c-d640-4aa2-9c2b-438deec7b64b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_7dc4fbfa-7cce-4a98-8b29-bd4f902f52f6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_53aadb01-3927-43c5-a06e-539333b7be67" xlink:to="loc_us-gaap_PlanNameAxis_7dc4fbfa-7cce-4a98-8b29-bd4f902f52f6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_d7145605-48a9-4a81-88ca-17492b5695f9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameAxis_7dc4fbfa-7cce-4a98-8b29-bd4f902f52f6" xlink:to="loc_us-gaap_PlanNameDomain_d7145605-48a9-4a81-88ca-17492b5695f9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_TwoThousandTwentyEquityIncentivePlanMember_93355257-f623-42c9-95ff-b195be4f8c1d" xlink:href="plrx-20220630.xsd#plrx_TwoThousandTwentyEquityIncentivePlanMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameDomain_d7145605-48a9-4a81-88ca-17492b5695f9" xlink:to="loc_plrx_TwoThousandTwentyEquityIncentivePlanMember_93355257-f623-42c9-95ff-b195be4f8c1d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_TwoThousandAndTwentyEmployeeStockPurchasePlanMember_8df2faba-6a38-46eb-97f7-b9958fd3fe08" xlink:href="plrx-20220630.xsd#plrx_TwoThousandAndTwentyEmployeeStockPurchasePlanMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameDomain_d7145605-48a9-4a81-88ca-17492b5695f9" xlink:to="loc_plrx_TwoThousandAndTwentyEmployeeStockPurchasePlanMember_8df2faba-6a38-46eb-97f7-b9958fd3fe08" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_4a42080c-8513-484f-bfe7-ae8782ec4b86" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_53aadb01-3927-43c5-a06e-539333b7be67" xlink:to="loc_us-gaap_ClassOfStockLineItems_4a42080c-8513-484f-bfe7-ae8782ec4b86" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_a11f971c-06da-4a33-9131-29c13bb93089" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ClassOfStockLineItems_4a42080c-8513-484f-bfe7-ae8782ec4b86" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_a11f971c-06da-4a33-9131-29c13bb93089" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensation" xlink:type="simple" xlink:href="plrx-20220630.xsd#EquityIncentivePlansandStockBasedCompensation"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensation" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_2b8c3b16-ffa2-4515-b828-9594f861a8d9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_d27cda16-23c9-4c67-8d51-c06e4bceb600" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_2b8c3b16-ffa2-4515-b828-9594f861a8d9" xlink:to="loc_us-gaap_DisclosureOfCompensationRelatedCostsShareBasedPaymentsTextBlock_d27cda16-23c9-4c67-8d51-c06e4bceb600" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationTables" xlink:type="simple" xlink:href="plrx-20220630.xsd#EquityIncentivePlansandStockBasedCompensationTables"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_09aaa49c-326e-4d0b-ab3e-a3afc735a4b5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock_5bba85ab-ce9e-48a8-a0db-56f45ba11269" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_09aaa49c-326e-4d0b-ab3e-a3afc735a4b5" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationRestrictedStockUnitsAwardActivityTableTextBlock_5bba85ab-ce9e-48a8-a0db-56f45ba11269" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_29b1cacc-a583-4714-8037-ad62c54d063a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_09aaa49c-326e-4d0b-ab3e-a3afc735a4b5" xlink:to="loc_us-gaap_ScheduleOfShareBasedPaymentAwardStockOptionsValuationAssumptionsTableTextBlock_29b1cacc-a583-4714-8037-ad62c54d063a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_9979a5b4-96c9-47ce-bcff-7f9076030b93" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_09aaa49c-326e-4d0b-ab3e-a3afc735a4b5" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationStockOptionsActivityTableTextBlock_9979a5b4-96c9-47ce-bcff-7f9076030b93" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock_132e288f-5be2-4c8c-b89f-c1af5fef84ee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_09aaa49c-326e-4d0b-ab3e-a3afc735a4b5" xlink:to="loc_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock_132e288f-5be2-4c8c-b89f-c1af5fef84ee" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedPaymentAwardEmployeeStockPurchasePlanValuationAssumptionsTableTextBlock_423c05ff-dc48-4019-884c-979168a5fbd0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedPaymentAwardEmployeeStockPurchasePlanValuationAssumptionsTableTextBlock"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_09aaa49c-326e-4d0b-ab3e-a3afc735a4b5" xlink:to="loc_us-gaap_ScheduleOfShareBasedPaymentAwardEmployeeStockPurchasePlanValuationAssumptionsTableTextBlock_423c05ff-dc48-4019-884c-979168a5fbd0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationEquityIncentivePlanNarrativeDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#EquityIncentivePlansandStockBasedCompensationEquityIncentivePlanNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationEquityIncentivePlanNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_8cbd3551-6a6e-4835-8630-29a7ab7d4ed1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_694a1d3a-7efe-49a2-bacd-f00224dcc6a2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_8cbd3551-6a6e-4835-8630-29a7ab7d4ed1" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_694a1d3a-7efe-49a2-bacd-f00224dcc6a2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_e7fe8b34-be4c-4da3-93cb-e9afcb5c4d0e" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_694a1d3a-7efe-49a2-bacd-f00224dcc6a2" xlink:to="loc_srt_RangeAxis_e7fe8b34-be4c-4da3-93cb-e9afcb5c4d0e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_ff3795ab-789c-4d8e-9d35-d10eaaf84b8c" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeAxis_e7fe8b34-be4c-4da3-93cb-e9afcb5c4d0e" xlink:to="loc_srt_RangeMember_ff3795ab-789c-4d8e-9d35-d10eaaf84b8c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_9ced0668-c47c-4c44-aa0d-c389be4defa3" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeMember_ff3795ab-789c-4d8e-9d35-d10eaaf84b8c" xlink:to="loc_srt_MaximumMember_9ced0668-c47c-4c44-aa0d-c389be4defa3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_91149aba-4a49-4e5b-a1a0-26dcfb126946" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_694a1d3a-7efe-49a2-bacd-f00224dcc6a2" xlink:to="loc_us-gaap_PlanNameAxis_91149aba-4a49-4e5b-a1a0-26dcfb126946" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_a057ae0c-9840-41dd-816e-5b13cef65580" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameAxis_91149aba-4a49-4e5b-a1a0-26dcfb126946" xlink:to="loc_us-gaap_PlanNameDomain_a057ae0c-9840-41dd-816e-5b13cef65580" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_TwoThousandFifteenEquityIncentivePlanMember_8e88cde4-7dcf-4c11-b74b-55918ac0f788" xlink:href="plrx-20220630.xsd#plrx_TwoThousandFifteenEquityIncentivePlanMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameDomain_a057ae0c-9840-41dd-816e-5b13cef65580" xlink:to="loc_plrx_TwoThousandFifteenEquityIncentivePlanMember_8e88cde4-7dcf-4c11-b74b-55918ac0f788" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_TwoThousandAndTwentyStockOptionsAndIncentivePlanMember_4430deef-1784-4e39-b6d8-0e7496f384a2" xlink:href="plrx-20220630.xsd#plrx_TwoThousandAndTwentyStockOptionsAndIncentivePlanMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameDomain_a057ae0c-9840-41dd-816e-5b13cef65580" xlink:to="loc_plrx_TwoThousandAndTwentyStockOptionsAndIncentivePlanMember_4430deef-1784-4e39-b6d8-0e7496f384a2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc508a3f-cb80-4ffe-a090-9bf6e88e38f7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_694a1d3a-7efe-49a2-bacd-f00224dcc6a2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc508a3f-cb80-4ffe-a090-9bf6e88e38f7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_30fe9247-7743-424f-812f-250cc1209d04" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc508a3f-cb80-4ffe-a090-9bf6e88e38f7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_30fe9247-7743-424f-812f-250cc1209d04" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_fa10cbcd-84c1-43c2-8add-8286e8587ad7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc508a3f-cb80-4ffe-a090-9bf6e88e38f7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_fa10cbcd-84c1-43c2-8add-8286e8587ad7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum_6bdc7c7a-9b9a-453a-9f14-5bcc16995ced" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc508a3f-cb80-4ffe-a090-9bf6e88e38f7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum_6bdc7c7a-9b9a-453a-9f14-5bcc16995ced" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_c4c6293f-17e8-44a0-a414-c61be4f57905" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc508a3f-cb80-4ffe-a090-9bf6e88e38f7" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_c4c6293f-17e8-44a0-a414-c61be4f57905" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_ShareBasedCompensationOptionsUnderPlanMayBeGrantedForPeriods_62714b56-4bb6-41aa-a4dd-ce95fb7e10e1" xlink:href="plrx-20220630.xsd#plrx_ShareBasedCompensationOptionsUnderPlanMayBeGrantedForPeriods"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc508a3f-cb80-4ffe-a090-9bf6e88e38f7" xlink:to="loc_plrx_ShareBasedCompensationOptionsUnderPlanMayBeGrantedForPeriods_62714b56-4bb6-41aa-a4dd-ce95fb7e10e1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentOfEstimatedFairValueOfShares_3d04df61-c5dd-4ccb-a737-976ce6387dab" xlink:href="plrx-20220630.xsd#plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentOfEstimatedFairValueOfShares"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc508a3f-cb80-4ffe-a090-9bf6e88e38f7" xlink:to="loc_plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentOfEstimatedFairValueOfShares_3d04df61-c5dd-4ccb-a737-976ce6387dab" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardExercisePriceWithPurchasePriceOfCommonStockPercentageOfEstimatedGrantDateFairValueForShareholders_79c58ce7-8360-4bed-9a7f-39f6a92696f8" xlink:href="plrx-20220630.xsd#plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardExercisePriceWithPurchasePriceOfCommonStockPercentageOfEstimatedGrantDateFairValueForShareholders"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc508a3f-cb80-4ffe-a090-9bf6e88e38f7" xlink:to="loc_plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardExercisePriceWithPurchasePriceOfCommonStockPercentageOfEstimatedGrantDateFairValueForShareholders_79c58ce7-8360-4bed-9a7f-39f6a92696f8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_04050251-5eb7-4085-a367-8e3fda0a9b7b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc508a3f-cb80-4ffe-a090-9bf6e88e38f7" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_04050251-5eb7-4085-a367-8e3fda0a9b7b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationRestrictedCommonStockAwardsNarrativeDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#EquityIncentivePlansandStockBasedCompensationRestrictedCommonStockAwardsNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationRestrictedCommonStockAwardsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_961432a2-9a77-4263-8d50-9ce28a4acefe" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1e437703-a855-41af-979e-5b2fdba467b6" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_961432a2-9a77-4263-8d50-9ce28a4acefe" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1e437703-a855-41af-979e-5b2fdba467b6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_e2ef0303-c36b-4a91-8f77-3a8a859cfcb8" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1e437703-a855-41af-979e-5b2fdba467b6" xlink:to="loc_srt_RangeAxis_e2ef0303-c36b-4a91-8f77-3a8a859cfcb8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_607dbec2-9e9c-4e7e-be02-d653843d1718" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeAxis_e2ef0303-c36b-4a91-8f77-3a8a859cfcb8" xlink:to="loc_srt_RangeMember_607dbec2-9e9c-4e7e-be02-d653843d1718" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_5c5de4de-15e9-4cdf-a790-3fefb812d1cd" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeMember_607dbec2-9e9c-4e7e-be02-d653843d1718" xlink:to="loc_srt_MinimumMember_5c5de4de-15e9-4cdf-a790-3fefb812d1cd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_3c89c73c-63b0-473a-ad10-9bc1374b0c78" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeMember_607dbec2-9e9c-4e7e-be02-d653843d1718" xlink:to="loc_srt_MaximumMember_3c89c73c-63b0-473a-ad10-9bc1374b0c78" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_dffb8c5d-8be8-418f-8c34-590117f3b9ea" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1e437703-a855-41af-979e-5b2fdba467b6" xlink:to="loc_us-gaap_PlanNameAxis_dffb8c5d-8be8-418f-8c34-590117f3b9ea" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_f08dedc8-21db-48d9-8b3e-194dd6799f91" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameAxis_dffb8c5d-8be8-418f-8c34-590117f3b9ea" xlink:to="loc_us-gaap_PlanNameDomain_f08dedc8-21db-48d9-8b3e-194dd6799f91" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_RestrictedCommonStockAwardsMember_9ecbb3dc-7623-45b1-8169-8a7ad54bf3f3" xlink:href="plrx-20220630.xsd#plrx_RestrictedCommonStockAwardsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameDomain_f08dedc8-21db-48d9-8b3e-194dd6799f91" xlink:to="loc_plrx_RestrictedCommonStockAwardsMember_9ecbb3dc-7623-45b1-8169-8a7ad54bf3f3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_41f21a1c-e98a-4436-b55a-f308e3005953" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1e437703-a855-41af-979e-5b2fdba467b6" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_41f21a1c-e98a-4436-b55a-f308e3005953" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_7e551d9f-12c5-4886-99e9-a7a2f125546f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_41f21a1c-e98a-4436-b55a-f308e3005953" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_7e551d9f-12c5-4886-99e9-a7a2f125546f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_AccruedExpensesAndOtherLiabilitiesMember_31ff05ce-ce74-445e-a376-388849ce6ff1" xlink:href="plrx-20220630.xsd#plrx_AccruedExpensesAndOtherLiabilitiesMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_7e551d9f-12c5-4886-99e9-a7a2f125546f" xlink:to="loc_plrx_AccruedExpensesAndOtherLiabilitiesMember_31ff05ce-ce74-445e-a376-388849ce6ff1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0b709b5a-fdb8-4436-8721-42bc83a85bb8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1e437703-a855-41af-979e-5b2fdba467b6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0b709b5a-fdb8-4436-8721-42bc83a85bb8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_3037b2c7-7af9-47c1-8aff-8edafba4a6ef" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0b709b5a-fdb8-4436-8721-42bc83a85bb8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_3037b2c7-7af9-47c1-8aff-8edafba4a6ef" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent_44becb3b-d4c0-4919-8975-6bdd795e850a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0b709b5a-fdb8-4436-8721-42bc83a85bb8" xlink:to="loc_us-gaap_DeferredCompensationShareBasedArrangementsLiabilityCurrent_44becb3b-d4c0-4919-8975-6bdd795e850a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_a5fc6a63-c1a8-4a5f-92ed-f3d286742bf4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0b709b5a-fdb8-4436-8721-42bc83a85bb8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_a5fc6a63-c1a8-4a5f-92ed-f3d286742bf4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueVested_408b1a88-2247-471c-a693-7dd1c56b1dca" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueVested"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0b709b5a-fdb8-4436-8721-42bc83a85bb8" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueVested_408b1a88-2247-471c-a693-7dd1c56b1dca" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding_439f47d9-6a58-4464-a7a2-4eb02943b376" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0b709b5a-fdb8-4436-8721-42bc83a85bb8" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsAggregateIntrinsicValueOutstanding_439f47d9-6a58-4464-a7a2-4eb02943b376" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationSummaryofRestrictedStockActivityDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#EquityIncentivePlansandStockBasedCompensationSummaryofRestrictedStockActivityDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationSummaryofRestrictedStockActivityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_1caa0985-fe17-4f87-bcc2-3b8d44a9c143" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_586426f8-8717-49ba-82d3-83324ae666ef" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_1caa0985-fe17-4f87-bcc2-3b8d44a9c143" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_586426f8-8717-49ba-82d3-83324ae666ef" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_8c780296-2e88-4e7a-8d1f-16b46e245a13" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_586426f8-8717-49ba-82d3-83324ae666ef" xlink:to="loc_us-gaap_PlanNameAxis_8c780296-2e88-4e7a-8d1f-16b46e245a13" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_3e7e0cc7-6c93-4afd-81cc-573f7f7b6f10" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameAxis_8c780296-2e88-4e7a-8d1f-16b46e245a13" xlink:to="loc_us-gaap_PlanNameDomain_3e7e0cc7-6c93-4afd-81cc-573f7f7b6f10" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_RestrictedCommonStockAwardsMember_8969c929-8dfb-47ff-be1c-3772dc8a2aa0" xlink:href="plrx-20220630.xsd#plrx_RestrictedCommonStockAwardsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameDomain_3e7e0cc7-6c93-4afd-81cc-573f7f7b6f10" xlink:to="loc_plrx_RestrictedCommonStockAwardsMember_8969c929-8dfb-47ff-be1c-3772dc8a2aa0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f98ece17-c86d-4d7d-8dac-49eca6dd8a94" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_586426f8-8717-49ba-82d3-83324ae666ef" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f98ece17-c86d-4d7d-8dac-49eca6dd8a94" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_aff132d7-4e55-44b4-b234-396a388ee565" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f98ece17-c86d-4d7d-8dac-49eca6dd8a94" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_aff132d7-4e55-44b4-b234-396a388ee565" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_7db59dd8-73fe-4035-8eeb-b084e0d13fe8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_aff132d7-4e55-44b4-b234-396a388ee565" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_7db59dd8-73fe-4035-8eeb-b084e0d13fe8" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_c1b1e2b6-7c1c-4ca7-a857-44cf171650df" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_aff132d7-4e55-44b4-b234-396a388ee565" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_c1b1e2b6-7c1c-4ca7-a857-44cf171650df" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_2b69b87f-b7ff-4e49-a15f-df8efc5392bb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_aff132d7-4e55-44b4-b234-396a388ee565" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_2b69b87f-b7ff-4e49-a15f-df8efc5392bb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsRepurchasesInPeriod_55d58fbf-dd29-4af0-b0d6-306712f25eed" xlink:href="plrx-20220630.xsd#plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsRepurchasesInPeriod"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_aff132d7-4e55-44b4-b234-396a388ee565" xlink:to="loc_plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsRepurchasesInPeriod_55d58fbf-dd29-4af0-b0d6-306712f25eed" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_c5900080-a100-4223-91cb-14e629a056ee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_aff132d7-4e55-44b4-b234-396a388ee565" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_c5900080-a100-4223-91cb-14e629a056ee" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_e767ee3c-6c30-4aa2-b895-5154fe988571" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f98ece17-c86d-4d7d-8dac-49eca6dd8a94" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_e767ee3c-6c30-4aa2-b895-5154fe988571" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_c7a29c8d-c95c-43e1-af3d-a125d6978b22" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_e767ee3c-6c30-4aa2-b895-5154fe988571" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_c7a29c8d-c95c-43e1-af3d-a125d6978b22" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_67054f46-fde9-46e5-ad69-2da00ce32e3f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_e767ee3c-6c30-4aa2-b895-5154fe988571" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_67054f46-fde9-46e5-ad69-2da00ce32e3f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_0af40211-fe38-4bfd-8c91-7f6c7c77ce3d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_e767ee3c-6c30-4aa2-b895-5154fe988571" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_0af40211-fe38-4bfd-8c91-7f6c7c77ce3d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsRepurchasesWeightedAverageGrantDateFairValue_0f153cb4-c07d-44a9-b14f-5eecc0f4b384" xlink:href="plrx-20220630.xsd#plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsRepurchasesWeightedAverageGrantDateFairValue"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_e767ee3c-6c30-4aa2-b895-5154fe988571" xlink:to="loc_plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsRepurchasesWeightedAverageGrantDateFairValue_0f153cb4-c07d-44a9-b14f-5eecc0f4b384" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_6791d181-3d55-4566-85b5-0b563cd36c9f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_e767ee3c-6c30-4aa2-b895-5154fe988571" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_6791d181-3d55-4566-85b5-0b563cd36c9f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationIncentiveStockOptionsandNonqualifiedStockOptionsNarrativeDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#EquityIncentivePlansandStockBasedCompensationIncentiveStockOptionsandNonqualifiedStockOptionsNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationIncentiveStockOptionsandNonqualifiedStockOptionsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_29c96616-635e-4c66-9be4-fe3485af4a62" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8d73f18f-b1c6-44a3-a111-a2c2e91ea0d5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_29c96616-635e-4c66-9be4-fe3485af4a62" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8d73f18f-b1c6-44a3-a111-a2c2e91ea0d5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_6c6e45d0-49d4-4c48-9a14-ceb06b1011d4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8d73f18f-b1c6-44a3-a111-a2c2e91ea0d5" xlink:to="loc_us-gaap_PlanNameAxis_6c6e45d0-49d4-4c48-9a14-ceb06b1011d4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_6ac30971-df84-427e-bc83-11c2d9d13ebf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameAxis_6c6e45d0-49d4-4c48-9a14-ceb06b1011d4" xlink:to="loc_us-gaap_PlanNameDomain_6ac30971-df84-427e-bc83-11c2d9d13ebf" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_TwoThousandFifteenAndTwoThousandTwentyEquityIncentivePlanMember_4045672d-03a6-4a9d-ad2d-d262e468209c" xlink:href="plrx-20220630.xsd#plrx_TwoThousandFifteenAndTwoThousandTwentyEquityIncentivePlanMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameDomain_6ac30971-df84-427e-bc83-11c2d9d13ebf" xlink:to="loc_plrx_TwoThousandFifteenAndTwoThousandTwentyEquityIncentivePlanMember_4045672d-03a6-4a9d-ad2d-d262e468209c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_TwoThousandAndTwentyStockOptionsAndIncentivePlanMember_e0559582-516f-438a-88d3-f076f3d596b4" xlink:href="plrx-20220630.xsd#plrx_TwoThousandAndTwentyStockOptionsAndIncentivePlanMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameDomain_6ac30971-df84-427e-bc83-11c2d9d13ebf" xlink:to="loc_plrx_TwoThousandAndTwentyStockOptionsAndIncentivePlanMember_e0559582-516f-438a-88d3-f076f3d596b4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_4587b4a3-935f-4710-850f-7f7a14429039" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8d73f18f-b1c6-44a3-a111-a2c2e91ea0d5" xlink:to="loc_us-gaap_AwardTypeAxis_4587b4a3-935f-4710-850f-7f7a14429039" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_31822a3e-173b-4264-8ec0-11fca6b63247" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_4587b4a3-935f-4710-850f-7f7a14429039" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_31822a3e-173b-4264-8ec0-11fca6b63247" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_IncentiveStockOptionsAndNonqualifiedStockOptionsMember_8f8961e9-6c05-47af-82aa-0cd6ea89ce8f" xlink:href="plrx-20220630.xsd#plrx_IncentiveStockOptionsAndNonqualifiedStockOptionsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_31822a3e-173b-4264-8ec0-11fca6b63247" xlink:to="loc_plrx_IncentiveStockOptionsAndNonqualifiedStockOptionsMember_8f8961e9-6c05-47af-82aa-0cd6ea89ce8f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_660b6cb1-4eed-4ae5-838a-22cf53ce3b54" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_8d73f18f-b1c6-44a3-a111-a2c2e91ea0d5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_660b6cb1-4eed-4ae5-838a-22cf53ce3b54" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_1a896689-9055-46f2-8910-45f38a683fdf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_660b6cb1-4eed-4ae5-838a-22cf53ce3b54" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_1a896689-9055-46f2-8910-45f38a683fdf" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_7e693c1e-43e8-4d43-afce-6c188a1b2714" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_660b6cb1-4eed-4ae5-838a-22cf53ce3b54" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_7e693c1e-43e8-4d43-afce-6c188a1b2714" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_f2883c3d-4457-4858-ba0e-6fbc62406cb1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_660b6cb1-4eed-4ae5-838a-22cf53ce3b54" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_f2883c3d-4457-4858-ba0e-6fbc62406cb1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_4e042b60-bfb3-46a5-af40-58a9bfe176b5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_660b6cb1-4eed-4ae5-838a-22cf53ce3b54" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_4e042b60-bfb3-46a5-af40-58a9bfe176b5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationSummaryofBlackScholesOptionPricingModeltoEstimateStockbasedCompensationExpenseforStockOptionAwardsDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#EquityIncentivePlansandStockBasedCompensationSummaryofBlackScholesOptionPricingModeltoEstimateStockbasedCompensationExpenseforStockOptionAwardsDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationSummaryofBlackScholesOptionPricingModeltoEstimateStockbasedCompensationExpenseforStockOptionAwardsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_509bb37d-fd6d-40b2-a2aa-a5f3a9482645" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0774d714-9a38-4cb5-9e53-561240b20bdb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_509bb37d-fd6d-40b2-a2aa-a5f3a9482645" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0774d714-9a38-4cb5-9e53-561240b20bdb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_0e620da0-0f47-43fe-be9e-843d9581913e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0774d714-9a38-4cb5-9e53-561240b20bdb" xlink:to="loc_us-gaap_AwardTypeAxis_0e620da0-0f47-43fe-be9e-843d9581913e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b5069a62-d29f-4bc7-8f8c-b997e0180b2c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_0e620da0-0f47-43fe-be9e-843d9581913e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b5069a62-d29f-4bc7-8f8c-b997e0180b2c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_IncentiveStockOptionsAndNonqualifiedStockOptionsMember_c48063e6-58c7-4751-8fec-3e4507b73098" xlink:href="plrx-20220630.xsd#plrx_IncentiveStockOptionsAndNonqualifiedStockOptionsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b5069a62-d29f-4bc7-8f8c-b997e0180b2c" xlink:to="loc_plrx_IncentiveStockOptionsAndNonqualifiedStockOptionsMember_c48063e6-58c7-4751-8fec-3e4507b73098" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_ee85b585-6451-450e-867c-b0dc5ee42027" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0774d714-9a38-4cb5-9e53-561240b20bdb" xlink:to="loc_srt_RangeAxis_ee85b585-6451-450e-867c-b0dc5ee42027" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_c194e1ca-fba8-420f-aae7-967876230f8f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeAxis_ee85b585-6451-450e-867c-b0dc5ee42027" xlink:to="loc_srt_RangeMember_c194e1ca-fba8-420f-aae7-967876230f8f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_799d9912-54c6-4407-a370-aacb06e11300" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeMember_c194e1ca-fba8-420f-aae7-967876230f8f" xlink:to="loc_srt_MinimumMember_799d9912-54c6-4407-a370-aacb06e11300" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_db36e497-d3d0-4e17-9c0a-f58be958850f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeMember_c194e1ca-fba8-420f-aae7-967876230f8f" xlink:to="loc_srt_MaximumMember_db36e497-d3d0-4e17-9c0a-f58be958850f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bcaf7222-c72a-444c-b00d-58f5c5ff8f37" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_0774d714-9a38-4cb5-9e53-561240b20bdb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bcaf7222-c72a-444c-b00d-58f5c5ff8f37" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum_edfabe53-1e5a-4c86-beae-c6a3ff6a242b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bcaf7222-c72a-444c-b00d-58f5c5ff8f37" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMinimum_edfabe53-1e5a-4c86-beae-c6a3ff6a242b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum_06647a23-3405-4dd4-b860-367974e5b817" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bcaf7222-c72a-444c-b00d-58f5c5ff8f37" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRateMaximum_06647a23-3405-4dd4-b860-367974e5b817" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum_9a1de8fc-a96a-4bf1-8629-5f07c6c70af3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bcaf7222-c72a-444c-b00d-58f5c5ff8f37" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMinimum_9a1de8fc-a96a-4bf1-8629-5f07c6c70af3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum_5ea07740-e58f-4559-aed9-f51686ea729c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bcaf7222-c72a-444c-b00d-58f5c5ff8f37" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRateMaximum_5ea07740-e58f-4559-aed9-f51686ea729c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_d27006b3-d405-4e7e-8655-a35510e9c6d5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bcaf7222-c72a-444c-b00d-58f5c5ff8f37" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_d27006b3-d405-4e7e-8655-a35510e9c6d5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_dc226d8c-888d-44ec-933d-2d38faf0f44a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bcaf7222-c72a-444c-b00d-58f5c5ff8f37" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_dc226d8c-888d-44ec-933d-2d38faf0f44a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_UnderlyingCommonStockFairValue_b6cb9ce0-4b1a-4ca5-b0f7-93c175d42fc5" xlink:href="plrx-20220630.xsd#plrx_UnderlyingCommonStockFairValue"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_bcaf7222-c72a-444c-b00d-58f5c5ff8f37" xlink:to="loc_plrx_UnderlyingCommonStockFairValue_b6cb9ce0-4b1a-4ca5-b0f7-93c175d42fc5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationSummaryofOptionActivityUnderthe2015Planand2020PlanDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#EquityIncentivePlansandStockBasedCompensationSummaryofOptionActivityUnderthe2015Planand2020PlanDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationSummaryofOptionActivityUnderthe2015Planand2020PlanDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_6d87e50f-5cc5-407f-92c6-5080f07b81e0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_16b88804-fd36-45ac-b5b7-cd93a80f5f01" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_6d87e50f-5cc5-407f-92c6-5080f07b81e0" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_16b88804-fd36-45ac-b5b7-cd93a80f5f01" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_a35b82e1-4043-4997-9d09-ac206c43f140" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_16b88804-fd36-45ac-b5b7-cd93a80f5f01" xlink:to="loc_us-gaap_PlanNameAxis_a35b82e1-4043-4997-9d09-ac206c43f140" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_f5992580-f28d-4214-acbb-35405b210862" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_PlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameAxis_a35b82e1-4043-4997-9d09-ac206c43f140" xlink:to="loc_us-gaap_PlanNameDomain_f5992580-f28d-4214-acbb-35405b210862" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_TwoThousandFifteenAndTwoThousandTwentyEquityIncentivePlanMember_e664e64a-0fe5-4f27-9405-c1cd31cfb86f" xlink:href="plrx-20220630.xsd#plrx_TwoThousandFifteenAndTwoThousandTwentyEquityIncentivePlanMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_PlanNameDomain_f5992580-f28d-4214-acbb-35405b210862" xlink:to="loc_plrx_TwoThousandFifteenAndTwoThousandTwentyEquityIncentivePlanMember_e664e64a-0fe5-4f27-9405-c1cd31cfb86f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_9330ba45-2637-42b3-b9fc-3c631f0b5ddb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_16b88804-fd36-45ac-b5b7-cd93a80f5f01" xlink:to="loc_us-gaap_AwardTypeAxis_9330ba45-2637-42b3-b9fc-3c631f0b5ddb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_255d1f0f-f025-45de-a932-308e6c85870f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_9330ba45-2637-42b3-b9fc-3c631f0b5ddb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_255d1f0f-f025-45de-a932-308e6c85870f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_IncentiveStockOptionsAndNonqualifiedStockOptionsMember_5ca1b500-9dbe-4f6e-a338-e95fd4475ded" xlink:href="plrx-20220630.xsd#plrx_IncentiveStockOptionsAndNonqualifiedStockOptionsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_255d1f0f-f025-45de-a932-308e6c85870f" xlink:to="loc_plrx_IncentiveStockOptionsAndNonqualifiedStockOptionsMember_5ca1b500-9dbe-4f6e-a338-e95fd4475ded" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc9ca51a-d424-42c8-8d36-14137a33f0ee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_16b88804-fd36-45ac-b5b7-cd93a80f5f01" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc9ca51a-d424-42c8-8d36-14137a33f0ee" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_95e6e38a-0388-4741-8c85-7e4b1b8ea6fb" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc9ca51a-d424-42c8-8d36-14137a33f0ee" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_95e6e38a-0388-4741-8c85-7e4b1b8ea6fb" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_85de9d5c-ea9e-440e-9ff2-5fc4ae52a56f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_95e6e38a-0388-4741-8c85-7e4b1b8ea6fb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_85de9d5c-ea9e-440e-9ff2-5fc4ae52a56f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_4a39dbce-e351-4ace-9d02-7c08232e8f1a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_95e6e38a-0388-4741-8c85-7e4b1b8ea6fb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_4a39dbce-e351-4ace-9d02-7c08232e8f1a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_3c57f1d7-096a-4d1b-bb24-98e38878013a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_95e6e38a-0388-4741-8c85-7e4b1b8ea6fb" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_3c57f1d7-096a-4d1b-bb24-98e38878013a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_794df434-cad1-4d7b-9686-de0a3000c371" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_95e6e38a-0388-4741-8c85-7e4b1b8ea6fb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod_794df434-cad1-4d7b-9686-de0a3000c371" xlink:type="arc" preferredLabel="http://www.xbrl.org/2009/role/negatedLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_09340cce-38c3-4d76-88fb-c4826caeb993" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_95e6e38a-0388-4741-8c85-7e4b1b8ea6fb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_09340cce-38c3-4d76-88fb-c4826caeb993" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_3605700f-558e-4083-b2b2-d18ae631053e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_95e6e38a-0388-4741-8c85-7e4b1b8ea6fb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_3605700f-558e-4083-b2b2-d18ae631053e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber_ed67b79b-fe7a-4150-aedd-dc3e3fa847e2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_95e6e38a-0388-4741-8c85-7e4b1b8ea6fb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingNumber_ed67b79b-fe7a-4150-aedd-dc3e3fa847e2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_edb62e13-f688-48b2-9a51-9d3498f8213e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc9ca51a-d424-42c8-8d36-14137a33f0ee" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_edb62e13-f688-48b2-9a51-9d3498f8213e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_48ce8941-86b5-4075-8f1b-13c499e439d2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_edb62e13-f688-48b2-9a51-9d3498f8213e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_48ce8941-86b5-4075-8f1b-13c499e439d2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodStartLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_d788ed94-e428-416a-9092-bb1e4b19f7b9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_edb62e13-f688-48b2-9a51-9d3498f8213e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice_d788ed94-e428-416a-9092-bb1e4b19f7b9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_10d65a46-34bc-4acd-a5e2-69d2beab8823" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_edb62e13-f688-48b2-9a51-9d3498f8213e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_10d65a46-34bc-4acd-a5e2-69d2beab8823" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_d5d0f9a7-f7d7-4d57-a35b-06f4b07d60d0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_edb62e13-f688-48b2-9a51-9d3498f8213e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice_d5d0f9a7-f7d7-4d57-a35b-06f4b07d60d0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_ac63a8b9-0ea9-49bd-a29f-c7c26e49cc01" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_edb62e13-f688-48b2-9a51-9d3498f8213e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_ac63a8b9-0ea9-49bd-a29f-c7c26e49cc01" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/periodEndLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_d61839d4-7666-4092-8266-1aa5999015ab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc9ca51a-d424-42c8-8d36-14137a33f0ee" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_d61839d4-7666-4092-8266-1aa5999015ab" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_47c91633-46ed-43cc-b5e9-283376da930f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc9ca51a-d424-42c8-8d36-14137a33f0ee" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageExercisePrice_47c91633-46ed-43cc-b5e9-283376da930f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_1516f811-1221-4941-a8c8-332cb45f0a5e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc9ca51a-d424-42c8-8d36-14137a33f0ee" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_1516f811-1221-4941-a8c8-332cb45f0a5e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_598c8601-0097-48e0-b48c-7cd7785b152d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc9ca51a-d424-42c8-8d36-14137a33f0ee" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_598c8601-0097-48e0-b48c-7cd7785b152d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_683c45a0-7ea1-44ab-9fcf-bb51e3a93adc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc9ca51a-d424-42c8-8d36-14137a33f0ee" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm1_683c45a0-7ea1-44ab-9fcf-bb51e3a93adc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_6966e02c-bd4e-48da-b6a1-58545cc5633e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc9ca51a-d424-42c8-8d36-14137a33f0ee" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue_6966e02c-bd4e-48da-b6a1-58545cc5633e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_a5827e96-05b0-4ce5-820a-a82410d65f91" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1"/>
    <link:presentationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc9ca51a-d424-42c8-8d36-14137a33f0ee" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1_a5827e96-05b0-4ce5-820a-a82410d65f91" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_5c7f5e8c-d7aa-4694-b947-44cea933169f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue"/>
    <link:presentationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc9ca51a-d424-42c8-8d36-14137a33f0ee" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestOutstandingAggregateIntrinsicValue_5c7f5e8c-d7aa-4694-b947-44cea933169f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationSummaryofStockbasedCompensationExpenseDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#EquityIncentivePlansandStockBasedCompensationSummaryofStockbasedCompensationExpenseDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationSummaryofStockbasedCompensationExpenseDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_3c9e4684-8fb3-436c-98b9-d32976bfb2ae" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_7457c259-61e9-4eb6-8197-927b6718aca9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_3c9e4684-8fb3-436c-98b9-d32976bfb2ae" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_7457c259-61e9-4eb6-8197-927b6718aca9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_90fb44cd-3c0a-4ad5-8179-c3bc09e8ca96" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_7457c259-61e9-4eb6-8197-927b6718aca9" xlink:to="loc_us-gaap_AwardTypeAxis_90fb44cd-3c0a-4ad5-8179-c3bc09e8ca96" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_eef9903c-2e6b-4240-b2a9-40a0503e879b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_90fb44cd-3c0a-4ad5-8179-c3bc09e8ca96" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_eef9903c-2e6b-4240-b2a9-40a0503e879b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_RestrictedCommonStockAwardsMember_126b5c61-a993-49e4-9a89-b2f9ed2c6f72" xlink:href="plrx-20220630.xsd#plrx_RestrictedCommonStockAwardsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_eef9903c-2e6b-4240-b2a9-40a0503e879b" xlink:to="loc_plrx_RestrictedCommonStockAwardsMember_126b5c61-a993-49e4-9a89-b2f9ed2c6f72" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_EmployeeStockOptionAndPurchasePlanMember_316b33eb-1e59-4df8-9fa0-6c23339e9ddd" xlink:href="plrx-20220630.xsd#plrx_EmployeeStockOptionAndPurchasePlanMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_eef9903c-2e6b-4240-b2a9-40a0503e879b" xlink:to="loc_plrx_EmployeeStockOptionAndPurchasePlanMember_316b33eb-1e59-4df8-9fa0-6c23339e9ddd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_6519d41b-b3c9-4f7e-bd10-5b12decc9349" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_7457c259-61e9-4eb6-8197-927b6718aca9" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_6519d41b-b3c9-4f7e-bd10-5b12decc9349" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_3b60fd82-292d-49f0-b0e2-a2804f425c77" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_6519d41b-b3c9-4f7e-bd10-5b12decc9349" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_3b60fd82-292d-49f0-b0e2-a2804f425c77" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_660adb2b-6f92-45d6-b75a-ca2cc525f2db" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ResearchAndDevelopmentExpenseMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_3b60fd82-292d-49f0-b0e2-a2804f425c77" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_660adb2b-6f92-45d6-b75a-ca2cc525f2db" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_9f2e40c3-c52c-42db-8cad-86325995dc9a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_GeneralAndAdministrativeExpenseMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_3b60fd82-292d-49f0-b0e2-a2804f425c77" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_9f2e40c3-c52c-42db-8cad-86325995dc9a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14c9b161-0035-4a04-bcd6-120a7d8122d4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_7457c259-61e9-4eb6-8197-927b6718aca9" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14c9b161-0035-4a04-bcd6-120a7d8122d4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_5a9482f2-1b5d-449a-aebc-c4ec6def2e1c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_14c9b161-0035-4a04-bcd6-120a7d8122d4" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_5a9482f2-1b5d-449a-aebc-c4ec6def2e1c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationStockBasedCompensationNarrativeDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#EquityIncentivePlansandStockBasedCompensationStockBasedCompensationNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensationStockBasedCompensationNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_6ffe0622-1482-49f6-bbfa-9e65d9260cba" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_de65b139-cce3-4fae-9290-f407da1d0c3e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_6ffe0622-1482-49f6-bbfa-9e65d9260cba" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_de65b139-cce3-4fae-9290-f407da1d0c3e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_e8d3937f-bbb2-42c3-80a3-e1e55b3795a0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_de65b139-cce3-4fae-9290-f407da1d0c3e" xlink:to="loc_us-gaap_AwardTypeAxis_e8d3937f-bbb2-42c3-80a3-e1e55b3795a0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_555ba124-28d9-4b3f-aae1-9298764e5fdd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_e8d3937f-bbb2-42c3-80a3-e1e55b3795a0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_555ba124-28d9-4b3f-aae1-9298764e5fdd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_RestrictedStockAwardsMember_029c8eb2-367b-4519-8e63-bdd962286a95" xlink:href="plrx-20220630.xsd#plrx_RestrictedStockAwardsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_555ba124-28d9-4b3f-aae1-9298764e5fdd" xlink:to="loc_plrx_RestrictedStockAwardsMember_029c8eb2-367b-4519-8e63-bdd962286a95" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_e74b5009-4c91-4420-9539-dc1f66c06909" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_555ba124-28d9-4b3f-aae1-9298764e5fdd" xlink:to="loc_us-gaap_EmployeeStockOptionMember_e74b5009-4c91-4420-9539-dc1f66c06909" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_94dfb297-fab5-4403-b564-b92ee235602f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_de65b139-cce3-4fae-9290-f407da1d0c3e" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_94dfb297-fab5-4403-b564-b92ee235602f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_1490d5c0-9039-4c4d-b498-fb9e68542302" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_94dfb297-fab5-4403-b564-b92ee235602f" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_1490d5c0-9039-4c4d-b498-fb9e68542302" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_70b8dd8b-71b9-4eb3-9050-2ba94eaa0643" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_94dfb297-fab5-4403-b564-b92ee235602f" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_70b8dd8b-71b9-4eb3-9050-2ba94eaa0643" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_293b472a-e21b-4e01-aeac-bf29a294d40c" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_94dfb297-fab5-4403-b564-b92ee235602f" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_293b472a-e21b-4e01-aeac-bf29a294d40c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensation2020EmployeeStockPurchasePlanNarrativeDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#EquityIncentivePlansandStockBasedCompensation2020EmployeeStockPurchasePlanNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensation2020EmployeeStockPurchasePlanNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_b77ff9f1-8975-463a-8a20-fe457011c251" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_4be1001a-c1a8-46ec-a2f6-95caebb13fb7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_b77ff9f1-8975-463a-8a20-fe457011c251" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_4be1001a-c1a8-46ec-a2f6-95caebb13fb7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_9751efad-7e8d-4dca-9653-3c2b21ed7d66" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_4be1001a-c1a8-46ec-a2f6-95caebb13fb7" xlink:to="loc_us-gaap_AwardTypeAxis_9751efad-7e8d-4dca-9653-3c2b21ed7d66" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_7200f99f-1e8f-4ee6-bdb2-36c5c1bc1f3a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_9751efad-7e8d-4dca-9653-3c2b21ed7d66" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_7200f99f-1e8f-4ee6-bdb2-36c5c1bc1f3a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_TwoThousandAndTwentyEmployeeStockPurchasePlanMember_a5d85330-de88-4729-8d06-529da4533bec" xlink:href="plrx-20220630.xsd#plrx_TwoThousandAndTwentyEmployeeStockPurchasePlanMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_7200f99f-1e8f-4ee6-bdb2-36c5c1bc1f3a" xlink:to="loc_plrx_TwoThousandAndTwentyEmployeeStockPurchasePlanMember_a5d85330-de88-4729-8d06-529da4533bec" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a8b6b1bf-53a6-4ef3-99b8-ac9320e0e714" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_4be1001a-c1a8-46ec-a2f6-95caebb13fb7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a8b6b1bf-53a6-4ef3-99b8-ac9320e0e714" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_9129bf68-f9c3-44c3-9c4a-15fb269adb06" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a8b6b1bf-53a6-4ef3-99b8-ac9320e0e714" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_9129bf68-f9c3-44c3-9c4a-15fb269adb06" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum_deaf2236-14c9-4044-a05e-1c15a138bf66" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a8b6b1bf-53a6-4ef3-99b8-ac9320e0e714" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardPercentageOfOutstandingStockMaximum_deaf2236-14c9-4044-a05e-1c15a138bf66" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate_f3dc4097-1d19-4065-b0e2-0505c1dfa9f0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a8b6b1bf-53a6-4ef3-99b8-ac9320e0e714" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate_f3dc4097-1d19-4065-b0e2-0505c1dfa9f0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_EmployeeStockPurchasePlanOfferingPeriod_6a4197c3-2488-4b85-9570-e87772a0184b" xlink:href="plrx-20220630.xsd#plrx_EmployeeStockPurchasePlanOfferingPeriod"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a8b6b1bf-53a6-4ef3-99b8-ac9320e0e714" xlink:to="loc_plrx_EmployeeStockPurchasePlanOfferingPeriod_6a4197c3-2488-4b85-9570-e87772a0184b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_CommonStockFairMarketValuePercentage_973c9594-bf14-4d3f-9ca8-0d58fc71b2ae" xlink:href="plrx-20220630.xsd#plrx_CommonStockFairMarketValuePercentage"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a8b6b1bf-53a6-4ef3-99b8-ac9320e0e714" xlink:to="loc_plrx_CommonStockFairMarketValuePercentage_973c9594-bf14-4d3f-9ca8-0d58fc71b2ae" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_2e964545-aa59-4203-ae16-a21a05107bf4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a8b6b1bf-53a6-4ef3-99b8-ac9320e0e714" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_2e964545-aa59-4203-ae16-a21a05107bf4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod_712d6a8a-c0fb-48ba-bc93-5f1e45ca1a27" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a8b6b1bf-53a6-4ef3-99b8-ac9320e0e714" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod_712d6a8a-c0fb-48ba-bc93-5f1e45ca1a27" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensation2020EmployeeStockPurchasePlanSummaryofBlackScholesOptionPricingModeltoEstimateStockbasedCompensationExpensefor2020EmployeeStockPurchasePlanDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#EquityIncentivePlansandStockBasedCompensation2020EmployeeStockPurchasePlanSummaryofBlackScholesOptionPricingModeltoEstimateStockbasedCompensationExpensefor2020EmployeeStockPurchasePlanDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/EquityIncentivePlansandStockBasedCompensation2020EmployeeStockPurchasePlanSummaryofBlackScholesOptionPricingModeltoEstimateStockbasedCompensationExpensefor2020EmployeeStockPurchasePlanDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_0f6c8a03-2035-4020-9b2b-042496de3e96" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1dd21582-df4c-4181-9242-d584456f4814" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_DisclosureOfCompensationRelatedCostsSharebasedPaymentsAbstract_0f6c8a03-2035-4020-9b2b-042496de3e96" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1dd21582-df4c-4181-9242-d584456f4814" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_9a5b6d86-6401-4f87-b9eb-1835789b1224" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1dd21582-df4c-4181-9242-d584456f4814" xlink:to="loc_us-gaap_AwardTypeAxis_9a5b6d86-6401-4f87-b9eb-1835789b1224" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_bfae574e-58d7-4c20-a42e-1e5295b0b693" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_9a5b6d86-6401-4f87-b9eb-1835789b1224" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_bfae574e-58d7-4c20-a42e-1e5295b0b693" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_TwoThousandAndTwentyEmployeeStockPurchasePlanMember_6708d98e-83f3-4dd6-b0d4-561bf60f2a8a" xlink:href="plrx-20220630.xsd#plrx_TwoThousandAndTwentyEmployeeStockPurchasePlanMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_bfae574e-58d7-4c20-a42e-1e5295b0b693" xlink:to="loc_plrx_TwoThousandAndTwentyEmployeeStockPurchasePlanMember_6708d98e-83f3-4dd6-b0d4-561bf60f2a8a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a91a1bd1-542d-41f1-afad-d9df22ccc779" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_1dd21582-df4c-4181-9242-d584456f4814" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a91a1bd1-542d-41f1-afad-d9df22ccc779" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_632740b8-a5ae-4fc6-af57-f7db5de17993" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a91a1bd1-542d-41f1-afad-d9df22ccc779" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate_632740b8-a5ae-4fc6-af57-f7db5de17993" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_5de71282-99d8-43ae-bada-6bcb8eec7c4e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a91a1bd1-542d-41f1-afad-d9df22ccc779" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_5de71282-99d8-43ae-bada-6bcb8eec7c4e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_436ad248-225e-4fd9-a83c-258499706ec0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a91a1bd1-542d-41f1-afad-d9df22ccc779" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_436ad248-225e-4fd9-a83c-258499706ec0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_026aa667-e13e-4764-92ba-9eba030913de" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_a91a1bd1-542d-41f1-afad-d9df22ccc779" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate_026aa667-e13e-4764-92ba-9eba030913de" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/IncomeTaxes" xlink:type="simple" xlink:href="plrx-20220630.xsd#IncomeTaxes"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/IncomeTaxes" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxDisclosureAbstract_d1085fd7-f4d1-4bfb-b29a-5bdc122e7293" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxDisclosureTextBlock_233397c9-9a3c-4ac6-9484-2a55169debd3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxDisclosureTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_d1085fd7-f4d1-4bfb-b29a-5bdc122e7293" xlink:to="loc_us-gaap_IncomeTaxDisclosureTextBlock_233397c9-9a3c-4ac6-9484-2a55169debd3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/IncomeTaxesDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#IncomeTaxesDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/IncomeTaxesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxDisclosureAbstract_62f3f181-b662-4965-88a1-ab34cd10274f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_7e12eae8-479b-4791-8274-278484e4fb7f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_62f3f181-b662-4965-88a1-ab34cd10274f" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_7e12eae8-479b-4791-8274-278484e4fb7f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_ValuationAllowanceAsPercentageOnDeferredTaxAssets_82668635-4339-43c7-a592-984d20cb8b7e" xlink:href="plrx-20220630.xsd#plrx_ValuationAllowanceAsPercentageOnDeferredTaxAssets"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_62f3f181-b662-4965-88a1-ab34cd10274f" xlink:to="loc_plrx_ValuationAllowanceAsPercentageOnDeferredTaxAssets_82668635-4339-43c7-a592-984d20cb8b7e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_94ecedd8-ce68-4759-97a3-f6e0a7392570" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_62f3f181-b662-4965-88a1-ab34cd10274f" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_94ecedd8-ce68-4759-97a3-f6e0a7392570" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/CommitmentsandContingencies" xlink:type="simple" xlink:href="plrx-20220630.xsd#CommitmentsandContingencies"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/CommitmentsandContingencies" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_0a68eda7-cf1c-49f4-9d95-28dff5fe0423" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_308c81bf-1b44-46f1-a949-bfbb3d222ca2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommitmentsAndContingenciesDisclosureTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_0a68eda7-cf1c-49f4-9d95-28dff5fe0423" xlink:to="loc_us-gaap_CommitmentsAndContingenciesDisclosureTextBlock_308c81bf-1b44-46f1-a949-bfbb3d222ca2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/CommitmentsandContingenciesDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#CommitmentsandContingenciesDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/CommitmentsandContingenciesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_a3bff2a0-8d7f-45c0-93c7-535a215094e8" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CommitmentsAndContingenciesDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_ContractualArrangementsCancellationPeriod_a7949151-154a-4324-8e09-107d5c7147d0" xlink:href="plrx-20220630.xsd#plrx_ContractualArrangementsCancellationPeriod"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CommitmentsAndContingenciesDisclosureAbstract_a3bff2a0-8d7f-45c0-93c7-535a215094e8" xlink:to="loc_plrx_ContractualArrangementsCancellationPeriod_a7949151-154a-4324-8e09-107d5c7147d0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/Leases" xlink:type="simple" xlink:href="plrx-20220630.xsd#Leases"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/Leases" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAbstract_1a8029a0-37cc-4f53-b99e-7b0d06572fa1" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeasesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeasesTextBlock_b071399f-e200-4d88-ab7c-1605d9accc06" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeasesTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_1a8029a0-37cc-4f53-b99e-7b0d06572fa1" xlink:to="loc_us-gaap_LesseeOperatingLeasesTextBlock_b071399f-e200-4d88-ab7c-1605d9accc06" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/LeasesTables" xlink:type="simple" xlink:href="plrx-20220630.xsd#LeasesTables"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/LeasesTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAbstract_9eeff322-a0e0-4240-97b9-81bc9c0fe9f0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeasesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_e21278c5-908b-44b5-890c-a9622c9323f3" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_9eeff322-a0e0-4240-97b9-81bc9c0fe9f0" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock_e21278c5-908b-44b5-890c-a9622c9323f3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_AssetsAndLiabilitiesLesseeTableTextBlock_934200e1-d9c8-4207-84ae-aa03aa3173a3" xlink:href="plrx-20220630.xsd#plrx_AssetsAndLiabilitiesLesseeTableTextBlock"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_9eeff322-a0e0-4240-97b9-81bc9c0fe9f0" xlink:to="loc_plrx_AssetsAndLiabilitiesLesseeTableTextBlock_934200e1-d9c8-4207-84ae-aa03aa3173a3" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/LeasesNarrativeDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#LeasesNarrativeDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/LeasesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAbstract_45b667c9-e519-469e-b7f0-1d54d90ad43f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeasesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_344f98bd-2a3f-49b8-92e8-d4b829c5b4ea" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_45b667c9-e519-469e-b7f0-1d54d90ad43f" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_344f98bd-2a3f-49b8-92e8-d4b829c5b4ea" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_3aa497af-288e-44ef-b15e-7790343dab2f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_StatementGeographicalAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_344f98bd-2a3f-49b8-92e8-d4b829c5b4ea" xlink:to="loc_srt_StatementGeographicalAxis_3aa497af-288e-44ef-b15e-7790343dab2f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_a6980b90-435c-464f-bad2-cac308cfa8e4" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_SegmentGeographicalDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_StatementGeographicalAxis_3aa497af-288e-44ef-b15e-7790343dab2f" xlink:to="loc_srt_SegmentGeographicalDomain_a6980b90-435c-464f-bad2-cac308cfa8e4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_stpr_CA_e3ababc3-794e-40e2-b419-a0ba591d807a" xlink:href="https://xbrl.sec.gov/stpr/2022/stpr-2022.xsd#stpr_CA"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_SegmentGeographicalDomain_a6980b90-435c-464f-bad2-cac308cfa8e4" xlink:to="loc_stpr_CA_e3ababc3-794e-40e2-b419-a0ba591d807a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_ee0cb0c8-1b9e-40bd-a278-05918539dfc2" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_344f98bd-2a3f-49b8-92e8-d4b829c5b4ea" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_ee0cb0c8-1b9e-40bd-a278-05918539dfc2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_6c3d403f-d597-4312-b2cd-68577cb27f12" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_ee0cb0c8-1b9e-40bd-a278-05918539dfc2" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_6c3d403f-d597-4312-b2cd-68577cb27f12" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNoncurrentAssetsMember_e09077e9-fa9e-4be7-b6e8-a619d38dff70" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OtherNoncurrentAssetsMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_6c3d403f-d597-4312-b2cd-68577cb27f12" xlink:to="loc_us-gaap_OtherNoncurrentAssetsMember_e09077e9-fa9e-4be7-b6e8-a619d38dff70" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_49312314-fab6-47f8-9237-4c3b33718d72" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_344f98bd-2a3f-49b8-92e8-d4b829c5b4ea" xlink:to="loc_srt_RangeAxis_49312314-fab6-47f8-9237-4c3b33718d72" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e529d6ce-93a8-4801-b139-3c81e82e8113" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeAxis_49312314-fab6-47f8-9237-4c3b33718d72" xlink:to="loc_srt_RangeMember_e529d6ce-93a8-4801-b139-3c81e82e8113" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_c82ed16e-e0ea-468d-835c-364f9577231f" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeMember_e529d6ce-93a8-4801-b139-3c81e82e8113" xlink:to="loc_srt_MaximumMember_c82ed16e-e0ea-468d-835c-364f9577231f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_a30ea26d-4039-4c03-9b1b-afc9c2813cf7" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeMember_e529d6ce-93a8-4801-b139-3c81e82e8113" xlink:to="loc_srt_MinimumMember_a30ea26d-4039-4c03-9b1b-afc9c2813cf7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_dea0e1a7-26e5-4d7f-b194-573775816e7d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_344f98bd-2a3f-49b8-92e8-d4b829c5b4ea" xlink:to="loc_us-gaap_LesseeLeaseDescriptionLineItems_dea0e1a7-26e5-4d7f-b194-573775816e7d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_LeasedSpaceUnderNonCancellableOperatingLease_7b5a5066-7f42-44ed-b6a4-fe22dca053e1" xlink:href="plrx-20220630.xsd#plrx_LeasedSpaceUnderNonCancellableOperatingLease"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_dea0e1a7-26e5-4d7f-b194-573775816e7d" xlink:to="loc_plrx_LeasedSpaceUnderNonCancellableOperatingLease_7b5a5066-7f42-44ed-b6a4-fe22dca053e1" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseTermOfContract_bd871adb-5c81-4a2d-b59b-33461ff0b866" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseTermOfContract"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_dea0e1a7-26e5-4d7f-b194-573775816e7d" xlink:to="loc_us-gaap_LesseeOperatingLeaseTermOfContract_bd871adb-5c81-4a2d-b59b-33461ff0b866" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_PeriodOfBaseRentAbatement_fbecd77e-9b44-403d-aabc-84f7b542fbd2" xlink:href="plrx-20220630.xsd#plrx_PeriodOfBaseRentAbatement"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_dea0e1a7-26e5-4d7f-b194-573775816e7d" xlink:to="loc_plrx_PeriodOfBaseRentAbatement_fbecd77e-9b44-403d-aabc-84f7b542fbd2" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_BaseRentAbatedAmount_f43bacf4-cf37-4317-87f4-7168fef9bc11" xlink:href="plrx-20220630.xsd#plrx_BaseRentAbatedAmount"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_dea0e1a7-26e5-4d7f-b194-573775816e7d" xlink:to="loc_plrx_BaseRentAbatedAmount_f43bacf4-cf37-4317-87f4-7168fef9bc11" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SecurityDeposit_1b4cf5a6-e3c2-43c9-805c-eb6d41656c1a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SecurityDeposit"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_dea0e1a7-26e5-4d7f-b194-573775816e7d" xlink:to="loc_us-gaap_SecurityDeposit_1b4cf5a6-e3c2-43c9-805c-eb6d41656c1a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_4ed45c7d-eabe-46de-8753-3b88cea562cc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseRenewalTerm"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_dea0e1a7-26e5-4d7f-b194-573775816e7d" xlink:to="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_4ed45c7d-eabe-46de-8753-3b88cea562cc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_LeaseTermExtensionNoticePeriod_0b907f6a-e3e8-4fa5-8279-39aafefc621c" xlink:href="plrx-20220630.xsd#plrx_LeaseTermExtensionNoticePeriod"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_dea0e1a7-26e5-4d7f-b194-573775816e7d" xlink:to="loc_plrx_LeaseTermExtensionNoticePeriod_0b907f6a-e3e8-4fa5-8279-39aafefc621c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseCost_c434564c-c0d0-4b43-94a9-f1b7563067f9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseCost"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_dea0e1a7-26e5-4d7f-b194-573775816e7d" xlink:to="loc_us-gaap_OperatingLeaseCost_c434564c-c0d0-4b43-94a9-f1b7563067f9" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableLeaseCost_9adab815-3f93-4535-8579-336579a0c9ee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_VariableLeaseCost"/>
    <link:presentationArc order="9" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_dea0e1a7-26e5-4d7f-b194-573775816e7d" xlink:to="loc_us-gaap_VariableLeaseCost_9adab815-3f93-4535-8579-336579a0c9ee" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasePayments_1aebbfcc-29f0-4d3e-8106-01f7897733e4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeasePayments"/>
    <link:presentationArc order="10" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_dea0e1a7-26e5-4d7f-b194-573775816e7d" xlink:to="loc_us-gaap_OperatingLeasePayments_1aebbfcc-29f0-4d3e-8106-01f7897733e4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/LeasesScheduleofOperatingLeaseLiabilityDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#LeasesScheduleofOperatingLeaseLiabilityDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/LeasesScheduleofOperatingLeaseLiabilityDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAbstract_553081ff-8ee9-4444-8520-9c7e4509e645" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeasesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_634cb3b6-7661-4d79-a328-9a7f3ac3c63e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_553081ff-8ee9-4444-8520-9c7e4509e645" xlink:to="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_634cb3b6-7661-4d79-a328-9a7f3ac3c63e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_eaf13a99-395e-4c9d-a4a0-14897f3a14cf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_634cb3b6-7661-4d79-a328-9a7f3ac3c63e" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear_eaf13a99-395e-4c9d-a4a0-14897f3a14cf" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_0168b87c-c255-4496-8cbe-2e60e5cabc11" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_634cb3b6-7661-4d79-a328-9a7f3ac3c63e" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_0168b87c-c255-4496-8cbe-2e60e5cabc11" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_75c7e786-b200-4ac5-a76f-f4298b3808ae" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_634cb3b6-7661-4d79-a328-9a7f3ac3c63e" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_75c7e786-b200-4ac5-a76f-f4298b3808ae" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_b14b30cd-1408-478a-a0e3-6c5284dca5c5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_634cb3b6-7661-4d79-a328-9a7f3ac3c63e" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_b14b30cd-1408-478a-a0e3-6c5284dca5c5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_cdb63fea-95cc-4765-84a3-df4b5cb24dd5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_634cb3b6-7661-4d79-a328-9a7f3ac3c63e" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_cdb63fea-95cc-4765-84a3-df4b5cb24dd5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_f94df333-353f-4ca4-bf6f-3182928afdc4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_634cb3b6-7661-4d79-a328-9a7f3ac3c63e" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_f94df333-353f-4ca4-bf6f-3182928afdc4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_8e964bf0-7ea9-4334-9485-9e476c14d291" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_634cb3b6-7661-4d79-a328-9a7f3ac3c63e" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_8e964bf0-7ea9-4334-9485-9e476c14d291" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability_fc71b6b3-8ad4-40c2-a286-8c69ff15088e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseLiability"/>
    <link:presentationArc order="8" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_OperatingLeaseLiabilitiesPaymentsDueAbstract_634cb3b6-7661-4d79-a328-9a7f3ac3c63e" xlink:to="loc_us-gaap_OperatingLeaseLiability_fc71b6b3-8ad4-40c2-a286-8c69ff15088e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/LeasesScheduleofOperatingLeaseLiabilityDetails_1" xlink:type="simple" xlink:href="plrx-20220630.xsd#LeasesScheduleofOperatingLeaseLiabilityDetails_1"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/LeasesScheduleofOperatingLeaseLiabilityDetails_1" xlink:type="extended"/>
  <link:roleRef roleURI="http://www.pliantrx.com/role/LeasesWeightedaverageRemainingLeaseTermsandDiscountRatesDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#LeasesWeightedaverageRemainingLeaseTermsandDiscountRatesDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/LeasesWeightedaverageRemainingLeaseTermsandDiscountRatesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeasesAbstract_ecda8d32-57b7-4be9-ab91-5ba84b697161" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_LeasesAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_ee07d985-8534-4a7a-aaea-2f73d750562b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_ecda8d32-57b7-4be9-ab91-5ba84b697161" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_ee07d985-8534-4a7a-aaea-2f73d750562b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_b30bb126-05f5-4d90-8690-47cfd5620fab" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_LeasesAbstract_ecda8d32-57b7-4be9-ab91-5ba84b697161" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_b30bb126-05f5-4d90-8690-47cfd5620fab" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/RelatedPartyTransactions" xlink:type="simple" xlink:href="plrx-20220630.xsd#RelatedPartyTransactions"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/RelatedPartyTransactions" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsAbstract_086bce76-fe01-440e-8715-e034fa79a39f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsDisclosureTextBlock_2ffdd86f-4750-4274-93b7-929fada20729" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionsDisclosureTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RelatedPartyTransactionsAbstract_086bce76-fe01-440e-8715-e034fa79a39f" xlink:to="loc_us-gaap_RelatedPartyTransactionsDisclosureTextBlock_2ffdd86f-4750-4274-93b7-929fada20729" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/RelatedPartyTransactionsDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#RelatedPartyTransactionsDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/RelatedPartyTransactionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsAbstract_46d81caf-23c0-4c32-b2aa-e79efaa829d0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_22545834-2e4e-469b-a1d7-9ae549748c93" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RelatedPartyTransactionsAbstract_46d81caf-23c0-4c32-b2aa-e79efaa829d0" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_22545834-2e4e-469b-a1d7-9ae549748c93" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionAxis_3aa3468f-9904-4db0-8045-dde0947b084a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_22545834-2e4e-469b-a1d7-9ae549748c93" xlink:to="loc_us-gaap_RelatedPartyTransactionAxis_3aa3468f-9904-4db0-8045-dde0947b084a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionDomain_634e2772-27fc-4360-a077-af14c27a98c5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RelatedPartyTransactionAxis_3aa3468f-9904-4db0-8045-dde0947b084a" xlink:to="loc_us-gaap_RelatedPartyTransactionDomain_634e2772-27fc-4360-a077-af14c27a98c5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_ThirdRockVenturesMember_5814e6bd-c216-42e2-9ca7-7e67c010d6c7" xlink:href="plrx-20220630.xsd#plrx_ThirdRockVenturesMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RelatedPartyTransactionDomain_634e2772-27fc-4360-a077-af14c27a98c5" xlink:to="loc_plrx_ThirdRockVenturesMember_5814e6bd-c216-42e2-9ca7-7e67c010d6c7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_b0c6b06a-92a4-4c6f-bf1a-030205ea3aa6" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_TitleOfIndividualAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_22545834-2e4e-469b-a1d7-9ae549748c93" xlink:to="loc_srt_TitleOfIndividualAxis_b0c6b06a-92a4-4c6f-bf1a-030205ea3aa6" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_7e5a3e0a-ab3d-4e00-bf17-157977e727fc" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_TitleOfIndividualAxis_b0c6b06a-92a4-4c6f-bf1a-030205ea3aa6" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_7e5a3e0a-ab3d-4e00-bf17-157977e727fc" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_NonemployeeDirectorMember_80003a5e-9686-44b6-869d-75b447674f15" xlink:href="plrx-20220630.xsd#plrx_NonemployeeDirectorMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_7e5a3e0a-ab3d-4e00-bf17-157977e727fc" xlink:to="loc_plrx_NonemployeeDirectorMember_80003a5e-9686-44b6-869d-75b447674f15" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_cd558f9e-aba7-447d-ad26-43a829ef9f21" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_22545834-2e4e-469b-a1d7-9ae549748c93" xlink:to="loc_us-gaap_AwardTypeAxis_cd558f9e-aba7-447d-ad26-43a829ef9f21" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_95fd00de-6f00-4ff4-87d1-90f630e277bd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_cd558f9e-aba7-447d-ad26-43a829ef9f21" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_95fd00de-6f00-4ff4-87d1-90f630e277bd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_4bc3399c-a4a8-43bd-b4ad-1ebb95d682e4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_95fd00de-6f00-4ff4-87d1-90f630e277bd" xlink:to="loc_us-gaap_EmployeeStockOptionMember_4bc3399c-a4a8-43bd-b4ad-1ebb95d682e4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_ee86b6a1-1e97-4288-85bf-03c0567d0613" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_22545834-2e4e-469b-a1d7-9ae549748c93" xlink:to="loc_us-gaap_RelatedPartyTransactionLineItems_ee86b6a1-1e97-4288-85bf-03c0567d0613" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_5c37f6bc-f2ef-4323-82aa-803b3d57cd1b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_ee86b6a1-1e97-4288-85bf-03c0567d0613" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_5c37f6bc-f2ef-4323-82aa-803b3d57cd1b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodFairValue_a84b5694-f901-41b8-9fb0-43b1a1108864" xlink:href="plrx-20220630.xsd#plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodFairValue"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_ee86b6a1-1e97-4288-85bf-03c0567d0613" xlink:to="loc_plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodFairValue_a84b5694-f901-41b8-9fb0-43b1a1108864" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_464f8e65-1da8-48a1-be45-ed959e395b30" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_ee86b6a1-1e97-4288-85bf-03c0567d0613" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_464f8e65-1da8-48a1-be45-ed959e395b30" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRights_3728132a-3418-4f9e-a5c8-ee4c3febcdf0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRights"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_ee86b6a1-1e97-4288-85bf-03c0567d0613" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingRights_3728132a-3418-4f9e-a5c8-ee4c3febcdf0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/DefinedContributionPlan" xlink:type="simple" xlink:href="plrx-20220630.xsd#DefinedContributionPlan"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/DefinedContributionPlan" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CompensationAndRetirementDisclosureAbstract_fa3c83df-ca65-483e-aeb6-fdd2e2c72cb5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CompensationAndRetirementDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanTextBlock_bd799d54-e088-490b-a616-24545883bd3a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedContributionPlanTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CompensationAndRetirementDisclosureAbstract_fa3c83df-ca65-483e-aeb6-fdd2e2c72cb5" xlink:to="loc_us-gaap_DefinedContributionPlanTextBlock_bd799d54-e088-490b-a616-24545883bd3a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/DefinedContributionPlanDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#DefinedContributionPlanDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/DefinedContributionPlanDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CompensationAndRetirementDisclosureAbstract_2b680171-3e2a-4991-ac04-5913a3abf60a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_CompensationAndRetirementDisclosureAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedContributionPlanCostRecognized_524e5268-3244-4446-b7bc-89c16222b47b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_DefinedContributionPlanCostRecognized"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_CompensationAndRetirementDisclosureAbstract_2b680171-3e2a-4991-ac04-5913a3abf60a" xlink:to="loc_us-gaap_DefinedContributionPlanCostRecognized_524e5268-3244-4446-b7bc-89c16222b47b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/NetLossPerShareAttributabletoCommonStockholders" xlink:type="simple" xlink:href="plrx-20220630.xsd#NetLossPerShareAttributabletoCommonStockholders"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/NetLossPerShareAttributabletoCommonStockholders" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_0456fc88-2d1d-4f6f-a172-13d79845f541" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareTextBlock_82868501-3266-4c44-a224-425d7e856352" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_0456fc88-2d1d-4f6f-a172-13d79845f541" xlink:to="loc_us-gaap_EarningsPerShareTextBlock_82868501-3266-4c44-a224-425d7e856352" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/NetLossPerShareAttributabletoCommonStockholdersTables" xlink:type="simple" xlink:href="plrx-20220630.xsd#NetLossPerShareAttributabletoCommonStockholdersTables"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/NetLossPerShareAttributabletoCommonStockholdersTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_2afb8390-fca3-4972-8859-3bcc1990fced" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock_acb9547b-e4b0-46e7-b4eb-ffd4cf12b84a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_2afb8390-fca3-4972-8859-3bcc1990fced" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTextBlock_acb9547b-e4b0-46e7-b4eb-ffd4cf12b84a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_34229bb7-17be-45ce-b7e2-2d29d1b6c562" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_2afb8390-fca3-4972-8859-3bcc1990fced" xlink:to="loc_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_34229bb7-17be-45ce-b7e2-2d29d1b6c562" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/NetLossPerShareAttributabletoCommonStockholdersSummaryofPotentiallyDilutiveSecuritiesExcludedfromComputationofDilutedNetLossPerShareDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#NetLossPerShareAttributabletoCommonStockholdersSummaryofPotentiallyDilutiveSecuritiesExcludedfromComputationofDilutedNetLossPerShareDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/NetLossPerShareAttributabletoCommonStockholdersSummaryofPotentiallyDilutiveSecuritiesExcludedfromComputationofDilutedNetLossPerShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_b1bda1d9-9f3f-4e9a-8a3e-9216ad166f06" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_7f79ef49-c72b-4f90-a3f6-10d8b3a6f078" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_b1bda1d9-9f3f-4e9a-8a3e-9216ad166f06" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_7f79ef49-c72b-4f90-a3f6-10d8b3a6f078" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_7e8c16b4-f75a-4d1d-a0f3-72804fbee508" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_7f79ef49-c72b-4f90-a3f6-10d8b3a6f078" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_7e8c16b4-f75a-4d1d-a0f3-72804fbee508" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_4bab6e5c-c315-4dfc-a126-159741b1f682" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_7e8c16b4-f75a-4d1d-a0f3-72804fbee508" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_4bab6e5c-c315-4dfc-a126-159741b1f682" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockOptionMember_af44fd61-65d7-45c7-9d23-a3be955b93b4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EmployeeStockOptionMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_4bab6e5c-c315-4dfc-a126-159741b1f682" xlink:to="loc_us-gaap_EmployeeStockOptionMember_af44fd61-65d7-45c7-9d23-a3be955b93b4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_RestrictedStockAwardsGrantedAndNotPurchasedMember_40c4287f-b427-41ed-a443-48808a75b7da" xlink:href="plrx-20220630.xsd#plrx_RestrictedStockAwardsGrantedAndNotPurchasedMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_4bab6e5c-c315-4dfc-a126-159741b1f682" xlink:to="loc_plrx_RestrictedStockAwardsGrantedAndNotPurchasedMember_40c4287f-b427-41ed-a443-48808a75b7da" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_4aa5aa31-187a-4bf0-97be-7c460b60d26b" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestrictedStockMember"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_4bab6e5c-c315-4dfc-a126-159741b1f682" xlink:to="loc_us-gaap_RestrictedStockMember_4aa5aa31-187a-4bf0-97be-7c460b60d26b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_c231c694-eb49-4151-baf7-0a8f4bd7ed44" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_7f79ef49-c72b-4f90-a3f6-10d8b3a6f078" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_c231c694-eb49-4151-baf7-0a8f4bd7ed44" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_eb90e8b2-fb72-45e6-aadf-09f163460d5e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_c231c694-eb49-4151-baf7-0a8f4bd7ed44" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_eb90e8b2-fb72-45e6-aadf-09f163460d5e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/NetLossPerShareAttributabletoCommonStockholdersReconciliationofNumeratorandDenominatorUsedinCalculationofBasicandDilutedNetLossPerShareDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#NetLossPerShareAttributabletoCommonStockholdersReconciliationofNumeratorandDenominatorUsedinCalculationofBasicandDilutedNetLossPerShareDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/NetLossPerShareAttributabletoCommonStockholdersReconciliationofNumeratorandDenominatorUsedinCalculationofBasicandDilutedNetLossPerShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareReconciliationAbstract_1f4dc950-cf3a-42ee-b73e-511bf2bf89e9" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareReconciliationAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_453d854a-de41-48fb-adef-18a55728e2c4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareReconciliationAbstract_1f4dc950-cf3a-42ee-b73e-511bf2bf89e9" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_453d854a-de41-48fb-adef-18a55728e2c4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_a96cc9e4-83d5-477e-b41d-0b5f1920a25d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLoss"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_453d854a-de41-48fb-adef-18a55728e2c4" xlink:to="loc_us-gaap_NetIncomeLoss_a96cc9e4-83d5-477e-b41d-0b5f1920a25d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_1d4f9025-2ef1-4446-af3c-69813033f746" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasicAbstract_453d854a-de41-48fb-adef-18a55728e2c4" xlink:to="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_1d4f9025-2ef1-4446-af3c-69813033f746" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/totalLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_e7d49109-99f5-4a24-b85c-d2e123f09da7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareReconciliationAbstract_1f4dc950-cf3a-42ee-b73e-511bf2bf89e9" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_e7d49109-99f5-4a24-b85c-d2e123f09da7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_327f6be8-f030-4a5f-b987-23221de0a2a7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_e7d49109-99f5-4a24-b85c-d2e123f09da7" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_327f6be8-f030-4a5f-b987-23221de0a2a7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_14a63086-39cb-4392-9e00-45ae800589e5" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingDilutedDisclosureItemsAbstract_e7d49109-99f5-4a24-b85c-d2e123f09da7" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_14a63086-39cb-4392-9e00-45ae800589e5" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_d5adf838-1004-4314-b26c-ca0a5d2d5c2f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareReconciliationAbstract_1f4dc950-cf3a-42ee-b73e-511bf2bf89e9" xlink:to="loc_us-gaap_EarningsPerShareAbstract_d5adf838-1004-4314-b26c-ca0a5d2d5c2f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/verboseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_8cef9f3c-0bb3-4549-9faf-240917397478" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_d5adf838-1004-4314-b26c-ca0a5d2d5c2f" xlink:to="loc_us-gaap_EarningsPerShareBasic_8cef9f3c-0bb3-4549-9faf-240917397478" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_77187f5d-e156-40ce-b89c-3487751a2eee" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_EarningsPerShareAbstract_d5adf838-1004-4314-b26c-ca0a5d2d5c2f" xlink:to="loc_us-gaap_EarningsPerShareDiluted_77187f5d-e156-40ce-b89c-3487751a2eee" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/SubsequentEvents" xlink:type="simple" xlink:href="plrx-20220630.xsd#SubsequentEvents"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/SubsequentEvents" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventsAbstract_2b371364-e4c0-4adc-8985-5ac95988a1fc" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventsTextBlock_268c5d7f-9921-4e24-b0f5-e537bcc590cd" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventsTextBlock"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventsAbstract_2b371364-e4c0-4adc-8985-5ac95988a1fc" xlink:to="loc_us-gaap_SubsequentEventsTextBlock_268c5d7f-9921-4e24-b0f5-e537bcc590cd" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
  <link:roleRef roleURI="http://www.pliantrx.com/role/SubsequentEventsDetails" xlink:type="simple" xlink:href="plrx-20220630.xsd#SubsequentEventsDetails"/>
  <link:presentationLink xlink:role="http://www.pliantrx.com/role/SubsequentEventsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventsAbstract_fab70aa4-5def-4646-a9c5-a251c257876d" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_fa55b3d6-0cd4-44d3-8ab5-ae7dd0bc0562" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTable"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventsAbstract_fab70aa4-5def-4646-a9c5-a251c257876d" xlink:to="loc_us-gaap_SubsequentEventTable_fa55b3d6-0cd4-44d3-8ab5-ae7dd0bc0562" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsidiarySaleOfStockAxis_e0ae3cb4-ddd7-46ed-a769-10908471b329" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsidiarySaleOfStockAxis"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTable_fa55b3d6-0cd4-44d3-8ab5-ae7dd0bc0562" xlink:to="loc_us-gaap_SubsidiarySaleOfStockAxis_e0ae3cb4-ddd7-46ed-a769-10908471b329" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNameOfTransactionDomain_f2b51081-6d04-4606-9deb-c0d538ac1bbf" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SaleOfStockNameOfTransactionDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsidiarySaleOfStockAxis_e0ae3cb4-ddd7-46ed-a769-10908471b329" xlink:to="loc_us-gaap_SaleOfStockNameOfTransactionDomain_f2b51081-6d04-4606-9deb-c0d538ac1bbf" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IPOMember_ec33d9f2-1e51-4bd3-b659-472534a7c42a" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_IPOMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SaleOfStockNameOfTransactionDomain_f2b51081-6d04-4606-9deb-c0d538ac1bbf" xlink:to="loc_us-gaap_IPOMember_ec33d9f2-1e51-4bd3-b659-472534a7c42a" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CounterpartyNameAxis_194b709c-3dad-4a16-80d8-97fa813f3c1c" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_CounterpartyNameAxis"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTable_fa55b3d6-0cd4-44d3-8ab5-ae7dd0bc0562" xlink:to="loc_srt_CounterpartyNameAxis_194b709c-3dad-4a16-80d8-97fa813f3c1c" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RepurchaseAgreementCounterpartyNameDomain_e072f966-ac43-4677-a211-8de72c35f72e" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RepurchaseAgreementCounterpartyNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_CounterpartyNameAxis_194b709c-3dad-4a16-80d8-97fa813f3c1c" xlink:to="loc_srt_RepurchaseAgreementCounterpartyNameDomain_e072f966-ac43-4677-a211-8de72c35f72e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_UnderwritersMember_5dfc9ee3-8221-4117-832f-09a1a35b7889" xlink:href="plrx-20220630.xsd#plrx_UnderwritersMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RepurchaseAgreementCounterpartyNameDomain_e072f966-ac43-4677-a211-8de72c35f72e" xlink:to="loc_plrx_UnderwritersMember_5dfc9ee3-8221-4117-832f-09a1a35b7889" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_64a96170-0186-4dc7-9643-1f6d3cdc9046" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTable_fa55b3d6-0cd4-44d3-8ab5-ae7dd0bc0562" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_64a96170-0186-4dc7-9643-1f6d3cdc9046" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_2382f2f2-dd46-4712-b3bc-c712919c1eff" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_64a96170-0186-4dc7-9643-1f6d3cdc9046" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_2382f2f2-dd46-4712-b3bc-c712919c1eff" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_926294fe-4186-40b6-abae-279c9c459595" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_2382f2f2-dd46-4712-b3bc-c712919c1eff" xlink:to="loc_us-gaap_SubsequentEventMember_926294fe-4186-40b6-abae-279c9c459595" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_276bd719-6ad0-4407-9543-cef6038b62d0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_AwardTypeAxis"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTable_fa55b3d6-0cd4-44d3-8ab5-ae7dd0bc0562" xlink:to="loc_us-gaap_AwardTypeAxis_276bd719-6ad0-4407-9543-cef6038b62d0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f3225508-d5bd-4fc3-ab50-eb04242b678e" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_AwardTypeAxis_276bd719-6ad0-4407-9543-cef6038b62d0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f3225508-d5bd-4fc3-ab50-eb04242b678e" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_156527e7-cfb5-4c37-ab2e-089a206d7ec0" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f3225508-d5bd-4fc3-ab50-eb04242b678e" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_156527e7-cfb5-4c37-ab2e-089a206d7ec0" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_PerformanceRestrictedStockUnitsMember_eafc7abf-5111-4253-a9de-4adc6736570d" xlink:href="plrx-20220630.xsd#plrx_PerformanceRestrictedStockUnitsMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_f3225508-d5bd-4fc3-ab50-eb04242b678e" xlink:to="loc_plrx_PerformanceRestrictedStockUnitsMember_eafc7abf-5111-4253-a9de-4adc6736570d" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_29aa61ad-9324-4b66-8b1b-9607429ec03b" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeAxis"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTable_fa55b3d6-0cd4-44d3-8ab5-ae7dd0bc0562" xlink:to="loc_srt_RangeAxis_29aa61ad-9324-4b66-8b1b-9607429ec03b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_0cc8abcb-4fa4-4b86-b89a-c6d50aae5a46" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_RangeMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeAxis_29aa61ad-9324-4b66-8b1b-9607429ec03b" xlink:to="loc_srt_RangeMember_0cc8abcb-4fa4-4b86-b89a-c6d50aae5a46" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_9b1c978c-873f-4fef-a170-08118aed0312" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MinimumMember"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeMember_0cc8abcb-4fa4-4b86-b89a-c6d50aae5a46" xlink:to="loc_srt_MinimumMember_9b1c978c-873f-4fef-a170-08118aed0312" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_00594e27-c9e6-40ad-a75b-82d3bc474c8b" xlink:href="https://xbrl.fasb.org/srt/2022/elts/srt-2022.xsd#srt_MaximumMember"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_srt_RangeMember_0cc8abcb-4fa4-4b86-b89a-c6d50aae5a46" xlink:to="loc_srt_MaximumMember_00594e27-c9e6-40ad-a75b-82d3bc474c8b" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_ee38fa87-77bc-406e-b825-6999b988ffd7" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventTable_fa55b3d6-0cd4-44d3-8ab5-ae7dd0bc0562" xlink:to="loc_us-gaap_SubsequentEventLineItems_ee38fa87-77bc-406e-b825-6999b988ffd7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_b369edf9-4ed4-48db-bfc7-21819055ee03" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction"/>
    <link:presentationArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventLineItems_ee38fa87-77bc-406e-b825-6999b988ffd7" xlink:to="loc_us-gaap_SaleOfStockNumberOfSharesIssuedInTransaction_b369edf9-4ed4-48db-bfc7-21819055ee03" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockPricePerShare_b50a5cbc-3db0-42f4-acb8-9ecb5a3ce2db" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SaleOfStockPricePerShare"/>
    <link:presentationArc order="2" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventLineItems_ee38fa87-77bc-406e-b825-6999b988ffd7" xlink:to="loc_us-gaap_SaleOfStockPricePerShare_b50a5cbc-3db0-42f4-acb8-9ecb5a3ce2db" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleOfStockConsiderationReceivedOnTransaction_5c83ad26-2337-4cf4-97ad-3101e2c72d71" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SaleOfStockConsiderationReceivedOnTransaction"/>
    <link:presentationArc order="3" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventLineItems_ee38fa87-77bc-406e-b825-6999b988ffd7" xlink:to="loc_us-gaap_SaleOfStockConsiderationReceivedOnTransaction_5c83ad26-2337-4cf4-97ad-3101e2c72d71" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_e61fd158-ce07-40b9-98a4-fc3a18a0932f" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:presentationArc order="4" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventLineItems_ee38fa87-77bc-406e-b825-6999b988ffd7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_e61fd158-ce07-40b9-98a4-fc3a18a0932f" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_19ceeee6-99ce-4f73-8478-a623012d0775" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1"/>
    <link:presentationArc order="5" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventLineItems_ee38fa87-77bc-406e-b825-6999b988ffd7" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardRequisiteServicePeriod1_19ceeee6-99ce-4f73-8478-a623012d0775" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardTargetShares_d9ccdbe5-6d4b-419b-b7de-3da9800db9d7" xlink:href="plrx-20220630.xsd#plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardTargetShares"/>
    <link:presentationArc order="6" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventLineItems_ee38fa87-77bc-406e-b825-6999b988ffd7" xlink:to="loc_plrx_ShareBasedCompensationArrangementByShareBasedPaymentAwardTargetShares_d9ccdbe5-6d4b-419b-b7de-3da9800db9d7" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_9cc5ee55-6797-44f3-bf91-c8c444cde3d4" xlink:href="https://xbrl.fasb.org/us-gaap/2022/elts/us-gaap-2022.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage"/>
    <link:presentationArc order="7" xlink:arcrole="http://www.xbrl.org/2003/arcrole/parent-child" xlink:from="loc_us-gaap_SubsequentEventLineItems_ee38fa87-77bc-406e-b825-6999b988ffd7" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage_9cc5ee55-6797-44f3-bf91-c8c444cde3d4" xlink:type="arc" preferredLabel="http://www.xbrl.org/2003/role/terseLabel"/>
  </link:presentationLink>
</link:linkbase>
