Sunderland boss Regis Le Bris says it is "possible" that winger Romaine Mundle could miss the rest of the season following a return of his hamstring injury in Saturday's 1-0 win at West Brom.
The head coach told BBC Radio Newcastle's Nick Barnes: "We don't have a timeline. We are seeking other advice so we will have to wait."
Striker Eliezer Mayenda was selected as Mundle's replacement on the left-wing despite other options available on the bench.
Tommy Watson, who is joining Brighton in the summer, was an unused substitute and Enzo Le Fee previously played there before he was injured.