Carlisle manager Graham Kavanagh could be forced into the loan market following news defender Conor Townsend has broken a bone in his foot.
Townsend, on loan from Hull, sustained the injury during a training session in the gym and could be sidelined for up to six weeks.
The 20-year-old has fractured the fifth metatarsal in his left foot.
Fellow defender Chris Chantler, who has recently worked his way back from a long-term ankle problem, sustained an injury to his other ankle in a reserve-team game against Fleetwood this week and is awaiting the results of a scan.
The double blow leaves Kavanagh short of cover at left-back, with the versatile Matty Robson expected to resume in that position in Saturday's home game against Colchester.