diff --git a/wp-includes/ms-default-constants.php b/wp-includes/ms-default-constants.php
index c8dd091c0a..0f7d0ff6d3 100644
--- a/wp-includes/ms-default-constants.php
+++ b/wp-includes/ms-default-constants.php
@@ -114,12 +114,10 @@ function ms_file_constants() {
  * we will have translations loaded and can trigger warnings easily.
  *
  * @since 3.0.0
- *
- * @global boolean $subdomain_error
- * @global boolean $subdomain_error_warn
  */
 function ms_subdomain_constants() {
-	global $subdomain_error, $subdomain_error_warn;
+	static $subdomain_error = null;
+	static $subdomain_error_warn = null;
 
 	if ( false === $subdomain_error ) {
 		return;