The extent of his fitness concern has yet to be revealed, but it will come as a big blow to the Black Cats in their bid for a play-off place.
Clarke has been a key figure for the Wearside outfit this term, contributing 15 goals and four assists from 33 appearances in the Championship (all stats from Fbref).
The forward has also been the subject of transfer speculation this season, but has remained to play a key role in the team’s promotion push.
Jack Clarke injury latest
Interim head coach Mike Dodds will give a firm update on the fitness of Clarke later this week.
However, it has been claimed that he is a big doubt for this weekend’s clash against Swansea.
This will be Dodds’ first fixture in charge of the team since taking the reins of the squad back following Michael Beale’s dismissal earlier this week.
