Charlie Wyke's future is in the balance with Bradford City hoping to push through a deal for United's leading scorer.
The League One club put a bid in for Wyke last night, that is thought to have triggered a £250,000 release clause in the striker's contract.
Carlisle United said it could not confirm or deny Wyke's contract terms.
The clause gives Bradford permission to discuss the 24-year-old's career with him - making it Wyke's decision on whether he leaves the Blues.
With 17 goals this season, Wyke has scored nearly half of all the team's goals since mid-November.
The club has released this statement: