diff --git a/src/wp-includes/ms-functions.php b/src/wp-includes/ms-functions.php
index dafdea5a83..6722d4f727 100644
--- a/src/wp-includes/ms-functions.php
+++ b/src/wp-includes/ms-functions.php
@@ -136,10 +136,13 @@ function get_user_count() {
  *
  * @since MU 1.0
  *
- * @param int $id Optional. A site_id.
+ * @param int $network_id Deprecated, not supported.
  * @return int
  */
-function get_blog_count( $id = 0 ) {
+function get_blog_count( $network_id = 0 ) {
+	if ( func_num_args() )
+		_deprecated_argument( __FUNCTION__, '3.1' );
+
 	return get_site_option( 'blog_count' );
 }