diff --git a/model_utils/tracker.py b/model_utils/tracker.py
index 1c7d386..a9c7f70 100644
--- a/model_utils/tracker.py
+++ b/model_utils/tracker.py
@@ -63,7 +63,7 @@ class FieldInstanceTracker(object):
 
     def init_deferred_fields(self):
         self.instance._deferred_fields = []
-        if not self.instance._deferred:
+        if hasattr(self.instance, '_deferred') and not self.instance._deferred:
             return
 
         class DeferredAttributeTracker(DeferredAttribute):