Sunderland look set to be without Jonny Williams for the trip to Brentford tomorrow.
The Welsh international has damaged his hamstring and been unable to train this week for the Black Cats.
Sunderland, struggling in the Championship so far, are in the bottom three ahead of Saturday's clash at Griffin Park.
Williams, on loan from Crystal Palace, has impressed in the games he has featured in, but does have a history of injury problems already at the age of 24.
The Kent-born man played for Wales in their World Cup qualifier against Republic of Ireland recently, while he came on against Queens Park Rangers last weekend.
Sunderland boss Simon Grayson is disappointed with another setback for Williams.
He said: "It’s probably been the story of his career so far."
“I know he dislocated his shoulder at Ipswich but he just keeps getting a niggle here and there.
"That doesn’t help with my team selection because I want to play my most talented players and players that I’ve brought to this club to affect the game.
“Jonny showed last week what a good player he is. Could I have started him for that game?
"Not really, because I felt that he wasn’t in the right physical condition. That showed after the game when we found out he’d picked up a slight hamstring strain."