diff --git a/mod/assign/locallib.php b/mod/assign/locallib.php
index 4394cd285f7..62a3d0459a5 100644
--- a/mod/assign/locallib.php
+++ b/mod/assign/locallib.php
@@ -3719,7 +3719,9 @@ class assign {
      * @return bool
      */
     protected function gradebook_item_update($submission=null, $grade=null) {
+        global $CFG;
 
+        require_once($CFG->dirroot.'/mod/assign/lib.php');
         // Do not push grade to gradebook if blind marking is active as
         // the gradebook would reveal the students.
         if ($this->is_blind_marking()) {