diff --git a/src/wp-admin/includes/post.php b/src/wp-admin/includes/post.php
index 4dc46ac3df..cf8c8e9f01 100644
--- a/src/wp-admin/includes/post.php
+++ b/src/wp-admin/includes/post.php
@@ -1667,7 +1667,7 @@ function post_preview() {
 	} else {
 		$is_autosave = true;
 
-		if ( 'auto-draft' == $_POST['post_status'] )
+		if ( isset( $_POST['post_status'] ) && 'auto-draft' == $_POST['post_status'] )
 			$_POST['post_status'] = 'draft';
 
 		$saved_post_id = wp_create_post_autosave( $post->ID );