Right-back Otsemobor returned from a hamstring problem to play the full 90 minutes of the 2-1 defeat at Leeds on Monday night but has aggravated the injury and is doubtful.
Youngster George Francomb filled in for Otsemobor at Carlisle recently and is again on standby to start if required.
Midfielder Korey Smith missed the Leeds game with a thigh injury but has been training and is in contention while Luke Daley and Cody McDonald picked up knocks in the reserves' 3-1 win over Northampton in midweek.
Matt Gill made his return from a knee injury as a late substitute at Elland Road but is lacking match fitness while Owain Tudur-Jones is also close to a comeback from a calf injury.
Michael Nelson (ankle) and Michael Spillane (hamstring) remain sidelined as the Canaries look for a win to keep themselves in the play-off spots.