The former Leeds man underwent a scan on Wednesday last week, and the results should be in early this week and a final decision will be made on what is to happen next.
A club spokesman said:
"He saw the specialist last week and we are waiting to get the results some time this week. He also had treatment from the club physio over the weekend, so we want to see how he reacts to that, too, before deciding whether he needs an operation.''
Hackworth has had limited opportunities this season, making just 2 breif subs appearances and unable to force his way into the starting 11 as Mark Stallard, Danny Allsopp and Paul Heffernan are all above him in the pecking order.