Jason McAteer will be out of action for a further two months after undergoing a second hernia operation over the weekend.
The Sunderland midfielder suffered a relapse after the initial operation and was told he needed further surgery after seeing a specialist.
The Ireland star has been out of action since September and is unlikely to return before the end of February.
His absence adds to Black Cats boss Howard Wilkinson's injury headache as Claudio Reyna, Matt Piper, Julio Arca, Thomas Sorensen, Thomas Myhre and Thomas Butler are all still sidelined.