Hull could be without Richard Garcia, Nick Barmby and Mark Cullen against the Robins.
Australian midfielder Garcia sustained a knee injury during the first half of last week's goalless draw at Crystal Palace and is expected to miss out.
Veteran playmaker Barmby is definitely out due to a leg infection and striker Cullen has been ruled out due to a twisted ankle sustained in training.
Central defender Daniel Ayala is still struggling with a hamstring injury, but another centre-half, on-loan Anthony Gerrard, is expected to prove his fitness after being forced off against Palace with a calf injury.
Tigers manager Nigel Pearson has no other new injury or suspension problems as his side look to stretch their unbeaten league run to six matches.
Bristol City boss Keith Millen has no new problems.
Defender Liam Fontaine missed the home victory over Derby after sustaining an ankle injury in training last week.
He is set for at least a month on the sidelines on the advice of a specialist and Millen said: "I'll be sitting down with our medical staff to discuss the way forward. It's not great news and we may have to get another opinion."
Fellow defender Louis Carey has had an injection in his troublesome calf problem. The City skipper has not played since suffering the injury at Leeds on November 13 and could miss the entire Christmas schedule.
Marlon Jackson has returned from his loan spell at Aldershot but the striker is nursing a hamstring strain after playing for the reserves this week.
