The extent is now known and he will be out until the end of February.
Peter Taylor is relieved though that it is not a more serious injury, having been without the big centre forward for a whole year when he previously injured the same knee.
Elsewhere, Andy Dawson and Keith Andrews return after injuries when City play Cardiff on Saturday.
Taylor may also have Boaz Myhill available if his red card appeal is won. If not, the goalkeeper will serve a one-match ban.