diff --git a/lib/Cake/Log/Engine/FileLog.php b/lib/Cake/Log/Engine/FileLog.php
index 66d2ca5d2..988ed341f 100644
--- a/lib/Cake/Log/Engine/FileLog.php
+++ b/lib/Cake/Log/Engine/FileLog.php
@@ -182,7 +182,7 @@ class FileLog extends BaseLog {
  * Also if `rotate` count is reached oldest file is removed.
  *
  * @param string $filename Log file name
- * @return mixed True if rotated successfully or false in case of error.
+ * @return mixed True if rotated successfully or false in case of error, otherwise null.
  *   Void if file doesn't need to be rotated.
  */
 	protected function _rotateFile($filename) {