Bantams manager Peter Taylor is already without long-term absentees Simon Ramsden (calf/hip) and Steve Williams (hamstring), but Michael Flynn, yet to appear this season due to a hernia problem, could be included on the substitutes' bench
Bullock, who sustained the injury in Tuesday night's defeat at Aldershot is expected to be sidelined for a month.
Defender Ramsden, who has made only one appearance this season, has been back in full training for a fortnight and hopes to be in contention within the next two weeks.
Central defender Williams is three weeks away from a return, while midfielder Tommy Doherty (ankle) could be out for eight weeks as he is scheduled to have surgery.
Source: PA
Source: PA