diff --git a/node_revision_delete.module b/node_revision_delete.module
index 86907df..5f082ec 100755
--- a/node_revision_delete.module
+++ b/node_revision_delete.module
@@ -140,7 +140,7 @@ function node_revision_delete_cron() {
 
   if ($execute_revision_delete) {
     $max = variable_get('node_revision_delete_cron', NODE_REVISION_DELETE_CRON);
-    $tracked_content_types = node_revision_delete_content_types();
+    node_revision_delete_content_types();
     // Flag used to count how many have been deleted in this cron run.
     $total_deleted = 0;
     foreach (node_revision_delete_content_types() as $content_type => $revisions_to_keep) {