Sunderland midfield duo Jordan Henderson and Lee Cattermole could become the latest additions to the club's crippling injury list.
The Black Cats are already without a recognised striker for the final three games of the season and have a host of other players on the treatment table.
Now Steve Bruce has concerns over his dynamic midfield pair after they both suffered knocks in the dismal 3-0 defeat by Fulham last weekend.
Cattermole managed to play through the entire 90 minutes but Henderson left the fray with 15 minutes remaining and both will be monitored in the run-up to Saturday's clash with Bolton.
Bruce told the club's official website: "We will see how bad they are.
"We're doing everything we possible can. I've managed more than 500 games and I've never seen anything like this."
Bruce is hoping to have Ghana international John Mensah back in action after his adductor tear, but will not take a risk unless the defender is 100 per cent fit.
He added: "John trained for three days last week, but in the past I've put him in and he's broken down again.
"We'll look to give him a full week's training this week and take it from there."