Sunderland boss Chris Coleman fears being left with few options in central midfield after Darron Gibson suffered renewed groin problems against Barnsley.
The Republic of Ireland international had to be replaced after just over half an hour of the 1-0 loss to the Tykes at the Stadium of Light on New Year's Day, with Coleman already without Paddy McNair, Lee Cattermole, Didier Ndong and Jonny Williams.
And former Wales head coach Coleman is concerned that his struggling side may be without Gibson for a significant period of time.
He told the club's official website: "Darron thinks he has popped his groin, which doesn't sound good.
"We will have to wait and see - he will get scanned - but if it is what is suspected, then it is a big blow. Gibbo has been pulling the strings for us.
"He was just settling into the game and that happened, so I am bitterly disappointed, but we had no choice but to play him."
Gibson has made 15 Championship appearances for the Black Cats so far this season, having made the move to Wearside from Everton just under a year ago.
Sunderland are currently one from bottom in the Championship table, having won just four times in 26 league games so far this season
The Black Cats are priced at 1.001 to be relegated this season, with rock-bottom Birmingham City available at 15.00 and Hull City available at 501.00.
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