diff --git a/app/models/spree/adjustment.rb b/app/models/spree/adjustment.rb
index 02d38938cc..1f544b95e9 100644
--- a/app/models/spree/adjustment.rb
+++ b/app/models/spree/adjustment.rb
@@ -37,7 +37,6 @@ module Spree
     has_one :metadata, class_name: 'AdjustmentMetadata'
 
     belongs_to :adjustable, polymorphic: true
-    belongs_to :source, polymorphic: true
     belongs_to :originator, -> { with_deleted }, polymorphic: true
     belongs_to :order, class_name: "Spree::Order"