diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 3eee559ee1..36e48f0eaa 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -803,7 +803,8 @@ function status_header( $header ) {
 	if ( ('HTTP/1.1' != $protocol) && ('HTTP/1.0' != $protocol) )
 		$protocol = 'HTTP/1.0';
 	$status_header = "$protocol $header $text";
-	$status_header = apply_filters('status_header', $status_header, $header, $text, $protocol);
+	if ( function_exists('apply_filters') )
+		$status_header = apply_filters('status_header', $status_header, $header, $text, $protocol);
 
 	if ( version_compare( phpversion(), '4.3.0', '>=' ) ) {
 		return @header( $status_header, true, $header );