Manager Aidy Boothroyd remains hopeful he can lure Clarke Carlisle from Championship outfit Burnley to sign for Northampton.
The Cobblers boss took the experienced defender on loan from the Clarets last season and the 32-year-old is now out of contract.
Boothroyd told BBC Radio Northampton: "I think there is a chance [of him signing towards the end of pre-season].
"There are a lot of different variables when you are dealing with Clarke and there have not been any ultimatums."
He added: "When you try and bring players in, I think you have to treat every individual as a separate case," he added.
"As we are going along, things will evolve naturally. I think we do need a centre-half."