diff --git a/src/Monolog/Handler/SlackHandler.php b/src/Monolog/Handler/SlackHandler.php
index 59d4836f..c5428759 100644
--- a/src/Monolog/Handler/SlackHandler.php
+++ b/src/Monolog/Handler/SlackHandler.php
@@ -96,7 +96,8 @@ class SlackHandler extends SocketHandler
         $this->useAttachment = $useAttachment;
         $this->useShortAttachment = $useShortAttachment;
         $this->includeContextAndExtra = $includeContextAndExtra;
-        if ($this->includeContextAndExtra) {
+
+        if ($this->includeContextAndExtra && $this->useShortAttachment) {
             $this->lineFormatter = new LineFormatter;
         }
     }