diff --git a/eck.module b/eck.module
index 2c4028d..f24a17f 100644
--- a/eck.module
+++ b/eck.module
@@ -174,8 +174,8 @@ function eck_schema_alter(&$schema) {
       $entity_type_schema =
       eck_property_behavior_invoke_plugin_alter($entity_type, 'schema', array('entity_type' => $entity_type, 'schema' => $schema));
 
-      if ($entity_type_schema) {
-        $schema = array_merge($schema, $entity_type_schema);
+      if (isset($entity_type_schema['schema'])) {
+        $schema = array_merge($schema, $entity_type_schema['schema']);
       }
     }
   }