Carlisle United manager Greg Abbott is keen for Scott Vernon to join the club as part of the deal which would see Ben Williams move to Colchester United.
The Cumbrians accepted a bid for Williams last week, but the goalkeeper has yet to finalise his switch to League One rivals Colchester.
Abbott has confirmed that striker Vernon could now head in the opposite direction as he looks to bring in a replacement for Danny Graham.
However, Abbott has revealed that he is willing to scrap the whole transfer if there is no swift progress in the negotiations.
"I have put a bit of pressure on Colchester for the deal to happen," he told the Cumberland News.
"We weren't too bothered at the start, because Ben has done terrifically well for us. But we think the deal as it stands is a good one for the club.
"If it hasn't gone through by the end of Friday, we might end up calling it off.
"That will enable us to do something else, which is based on work that has been done on the back of that deal happening."