West Ham will check on Abdoulaye Faye ahead of the game.
The defender came off during Saturday's 3-2 win over Leicester with a tight hamstring but boss Sam Allardyce is hopeful he will be available.
James Tomkins came on as a substitute at the weekend after recovering from a groin injury and will start if Faye misses out.
Allardyce is still without a host of big names with midfielders David Bentley, Henri Lansbury (both knee) and Matt Taylor (calf) on the sidelines along with striker Carlton Cole (knee).
Right-back Guy Demel has a hamstring problem and winger Gary O'Neil is still out with an ankle injury.
Goalkeeper Robert Green returned after a knee operation on Saturday so Manuel Almunia has gone back to Arsenal following the end of his month-long loan.
Bristol City manager Derek McInnes looks set to keep faith with the side which won 2-1 at Barnsley on Saturday.
McInnes enjoyed his first victory as Robins boss as Oakwell while it was his new club's first success since a 2-1 win at Leicester on August 17.
The Ashton Gate outfit do have two long-term injury absentees, however, in defensive casualties Louis Carey and Jamie McAllister.
Veteran centre-back Carey is still suffering with a knee injury while McAllister continues his rehabilitation from an ankle knock and neither will be available to face the Hammers.
City go in search of their first win at Upton Park since February 1978, a wait of almost 34 years.