Sunderland boss Martin O'Neill admits it will be a blow if they've lost Stephane Sessegnon to injury.
Sessegnon broke down after firing Sunderland to their FA Cup win at Middlesbrough last night.
O'Neill said: "He is an outstanding player and I am delighted that we have him.
"He's really great. He hasn't missed a game - I hadn't realised he hasn't missed a game this season for us, which is outstanding.
"I hope it is just cramp rather than anything else."