diff --git a/wp-includes/ms-blogs.php b/wp-includes/ms-blogs.php
index 19bea526a6..7761e9007a 100644
--- a/wp-includes/ms-blogs.php
+++ b/wp-includes/ms-blogs.php
@@ -48,7 +48,7 @@ function get_blogaddress_by_name( $blogname ) {
 			$blogname = 'www';
 		$url = rtrim( network_home_url(), '/' );
 		if ( !empty( $blogname ) )
-			$url = preg_replace( '|^([^\.]+://)|', '$1' . $blogname . '.', $url );
+			$url = preg_replace( '|^([^\.]+://)|', "\${1}" . $blogname . '.', $url );
 	} else {
 		$url = network_home_url( $blogname );
 	}