diff --git a/plugins/checks/subcommands/run b/plugins/checks/subcommands/run
index 5be88e38f..dd9c6f935 100755
--- a/plugins/checks/subcommands/run
+++ b/plugins/checks/subcommands/run
@@ -52,6 +52,7 @@ check_process() {
     dokku_log_fail "Invalid container index specified ($APP.$PROC_TYPE.$CONTAINER_INDEX)"
   fi
 
+  IS_HEROKUISH_CONTAINER=false
   IMAGE=$(get_app_image_name "$APP")
   is_image_herokuish_based "$IMAGE" && IS_HEROKUISH_CONTAINER=true