Index: tests/Zend/Controller/Router/RewriteTest.php
===================================================================
--- tests/Zend/Controller/Router/RewriteTest.php	(revision 22179)
+++ tests/Zend/Controller/Router/RewriteTest.php	(working copy)
@@ -732,6 +732,37 @@
 
         $this->assertEquals('/articles/777', $url);
     }
+    
+
+    /**
+     * Test that it is possible to generate a URL with a numerical key
+     *
+     * @since  2010-05-16
+     * @group  ZF-8914
+     * @covers Zend_Controller_Router_Rewrite::assemble
+     */
+    public function testCanGenerateNumericKeyUri()
+    {
+        $this->_router->addRoute(
+            'default', 
+            new Zend_Controller_Router_Route(
+                ':controller/:action/*',
+                array('controller' => 'index', 'action' => 'index')
+            )
+       );
+
+       $params = array(
+            'controller' => 'index',
+            'action'     => 'index',
+            '2'          => 'foo',
+            'page'       => 'bar',
+        );
+
+        $this->assertEquals(
+            '/index/index/2/foo/page/bar',
+            $this->_router->assemble($params)
+        );
+    }
 }
 
 
Index: library/Zend/Controller/Router/Rewrite.php
===================================================================
--- library/Zend/Controller/Router/Rewrite.php	(revision 22179)
+++ library/Zend/Controller/Router/Rewrite.php	(working copy)
@@ -458,7 +458,8 @@
             }
         }
 
-        $params = array_merge($this->_globalParams, $userParams);
+        // Use UNION (+) in order to preserve numeric keys 
+        $params = $userParams + $this->_globalParams;
 
         $route = $this->getRoute($name);
         $url   = $route->assemble($params, $reset, $encode);