diff --git a/cms/djangoapps/contentstore/views/item.py b/cms/djangoapps/contentstore/views/item.py
index 8feaf96042..bc5cbb9158 100644
--- a/cms/djangoapps/contentstore/views/item.py
+++ b/cms/djangoapps/contentstore/views/item.py
@@ -114,7 +114,7 @@ def _is_library_component_limit_reached(usage_key):
 @require_http_methods(("DELETE", "GET", "PUT", "POST", "PATCH"))
 @login_required
 @expect_json
-def xblock_handler(request, usage_key_string):
+def xblock_handler(request, usage_key_string=None):
     """
     The restful handler for xblock requests.