diff --git a/pkgs/development/python-modules/polars/default.nix b/pkgs/development/python-modules/polars/default.nix
index d967ca27c8ff..5d1406fe3926 100644
--- a/pkgs/development/python-modules/polars/default.nix
+++ b/pkgs/development/python-modules/polars/default.nix
@@ -38,7 +38,6 @@ buildPythonPackage {
   # thus the `sed` command
   # Make sure to check that the right substitutions are made when updating the package
   preBuild = ''
-    cd py-polars
     #sed -i 's/version = "0.18.0"/version = "${version}"/g' Cargo.lock
   '';
 
@@ -49,7 +48,7 @@ buildPythonPackage {
     };
   };
 
-  cargoRoot = "py-polars";
+  sourceRoot = "source/py-polars";
 
   # Revisit this whenever package or Rust is upgraded
   RUSTC_BOOTSTRAP = 1;