The 22-year-old has been stalling over the terms of the deal but must make his mind up by next Tuesday when his current contract expires.
If Colbeck, who is keen to stay with Stuart McCall's side, fails to reach an agreement then he risks being placed on a week-to-week salary.
He was voted player of the year at the end of the 2007/8 campaign, but failed to recapture his best form last season after breaking a bone in his foot in October.
Source: Team_Talk
