Full-back Fabian Wilnis is set to undergo a scan on his thigh injury. The Dutchman has missed a number of recent matches with the problem and dropped out of Saturday's game at Birmingham during the warm-up.
Town's head of sports science Dave Williams told the club site: "Fabian felt his thigh again before kick-off at Birmingham and we will now have to see if there is an underlying problem.
"He will have a scan on Tuesday and we will go from there, but obviously at the moment he must be considered a doubt for the Sunderland game."
Midfielder Simon Walton has had the shin injury picked up in the first half at Birmingham stitched, but is not considered a concern for Saturday's home game with Sunderland.