Town full-back Fabian Wilnis could be out of action for as many as six weeks with the shoulder injury he picked up at Coventry on Saturday.
The injury is a serious loss to the Blues, Wilnis having been one of the most consistent performers this season.
Manager Joe Royle said: "It's a big blow and the last thing we needed right now. Fabian will be out for a month and it could be six weeks.
"He has not totally dislocated the shoulder, but he's sprung it. He was on the end of a bad tackle that saw their player booked and he's hurt himself as he's fallen to the ground."
Wilnis's absence gives Royle a problem with the full-back area not well covered by Town's squad.
The Town boss doesn't rule out a move into the loan market for a full-back but has a couple of options amongst his existing players: "We could change the system, although that's not something I want to be doing all the time, while Jermaine Wright has played there before.
"The trouble with Jermaine moving is that we miss his influence in midfield, but there's also young Scott Mitchell, who has been doing very well in the reserves."
Matt Richards is now Town's only fit senior full-back, Chris Makin still some way from a return to action after surgery.