--- django/db/models/related.py (revision 4668)
+++ django/db/models/related.py (working copy)
@@ -68,10 +68,13 @@
                 # object
                 return [attr]
         else:
-            if self.field.rel.min_num_in_admin:
-                return [None] * max(self.field.rel.num_in_admin, self.field.rel.min_num_in_admin)
+            if self.field.rel.multiple:
+                if self.field.rel.min_num_in_admin:
+                    return [None] * max(self.field.rel.num_in_admin, self.field.rel.min_num_in_admin)
+                else:
+                    return [None] * self.field.rel.num_in_admin
             else:
-                return [None] * self.field.rel.num_in_admin
+                return [None] * 1
 
     def get_db_prep_lookup(self, lookup_type, value):
         # Defer to the actual field definition for db prep
