diff --git a/modules/aggregator.module b/modules/aggregator.module
index 3a6d2d43e0f6aac5a8acb1f55c731e7ff965087f..148d052f734a99b07c025ce8605f4934d909a77a 100644
--- a/modules/aggregator.module
+++ b/modules/aggregator.module
@@ -193,7 +193,7 @@ function aggregator_cron() {
  *
  * Generates blocks for the latest news items in each category and feed.
  */
-function aggregator_block($op, $delta, $edit = array()) {
+function aggregator_block($op, $delta = 0, $edit = array()) {
   if (user_access('access news feeds')) {
     if ($op == 'list') {
       $result = db_query('SELECT cid, title FROM {aggregator_category} ORDER BY title');
diff --git a/modules/aggregator/aggregator.module b/modules/aggregator/aggregator.module
index 3a6d2d43e0f6aac5a8acb1f55c731e7ff965087f..148d052f734a99b07c025ce8605f4934d909a77a 100644
--- a/modules/aggregator/aggregator.module
+++ b/modules/aggregator/aggregator.module
@@ -193,7 +193,7 @@ function aggregator_cron() {
  *
  * Generates blocks for the latest news items in each category and feed.
  */
-function aggregator_block($op, $delta, $edit = array()) {
+function aggregator_block($op, $delta = 0, $edit = array()) {
   if (user_access('access news feeds')) {
     if ($op == 'list') {
       $result = db_query('SELECT cid, title FROM {aggregator_category} ORDER BY title');