The striker missed Sunderland's Barclays Premier League victory over Newcastle United last weekend and Gus Poyet, his manager, has admitted the injury, which has been troubling the 26-year-old for weeks, is worse than first thought and could require surgery. Poyet said: "It's affecting him more than I thought. I'm a bit worried. We're analysing it with the medical staff but we're going to have to make a decision one way or the other.
"We'll have to look at the games ahead and the chance of rest in between but we'll need to make a decision."