Defender Marcel Seip will miss the rest of City's season with a shoulder injury.
The Dutchman, whose short-term contract is up in the summer, has needed an operation.
Seip has missed the last three games since stirring up an old injury when he landed painfully on his shoulder during the 1-0 defeat at Aldershot.
The news comes as another defensive blow for Phil Parkinson, who is already without suspended centre halves Luke Oliver and Andrew Davies.
Parkinson said: “We’ll miss Marcel’s experience. But that was half the reason I kept Simon Ramsden back in midweek after we’d had the bad news from the scan.”