diff --git a/wp-blog-header.php b/wp-blog-header.php
index cc4aec4e7c..8ca6d65c62 100644
--- a/wp-blog-header.php
+++ b/wp-blog-header.php
@@ -33,7 +33,7 @@ if (! empty($_SERVER['PATH_INFO'])) {
         foreach ($rewrite as $match => $query) {
             // If the request URI is the anchor of the match, prepend it
             // to the path info.
-            if (preg_match("!^$req_uri!", $match)) {
+            if (strpos($match, $req_uri) === 0) {
                 $pathinfomatch = $req_uri . '/' . $pathinfo;
             }