diff --git a/crates/uv-python/src/installation.rs b/crates/uv-python/src/installation.rs
index 48dcd2f04..7a17ed4f0 100644
--- a/crates/uv-python/src/installation.rs
+++ b/crates/uv-python/src/installation.rs
@@ -88,7 +88,7 @@ impl PythonInstallation {
         // Perform a fetch aggressively if managed Python is preferred
         if matches!(preference, PythonPreference::Managed) && python_fetch.is_automatic() {
             if let Some(request) = PythonDownloadRequest::try_from_request(&request) {
-                return Self::fetch(request, client_builder, cache).await;
+                return Self::fetch(request.fill(), client_builder, cache).await;
             }
         }
 
@@ -103,7 +103,7 @@ impl PythonInstallation {
             {
                 if let Some(request) = PythonDownloadRequest::try_from_request(&request) {
                     debug!("Requested Python not found, checking for available download...");
-                    Self::fetch(request, client_builder, cache).await
+                    Self::fetch(request.fill(), client_builder, cache).await
                 } else {
                     err
                 }