diff --git a/cloud/amazon/elasticache.py b/cloud/amazon/elasticache.py
index f163ad312e8..6586a018a8d 100644
--- a/cloud/amazon/elasticache.py
+++ b/cloud/amazon/elasticache.py
@@ -42,6 +42,7 @@ options:
     description:
       - The version number of the cache engine
     required: false
+    default: none
   node_type:
     description:
       - The compute and memory capacity of the nodes in the cache cluster