Sunderland have been dealt a injury blow after captain Lee Cattermole was ruled out for two months with a knee problem.
Cattermole limped off in Sunderland's goalless draw against Queens Park Rangers last month with suspected medial ligament damage.
The midfielder travelled to London to see a specialist, who confirmed he will likely be out until early February.
"He'll probably be about another two months," Sunderland manager Martin O'Neill said.
"I knew the news wouldn't be too good. It could have been worse but obviously it could have been better."
Cattermole is expected to miss up to 12 English Premier League games, with O'Neill now considering whether to recall midfielder David Meyler.
Meyler, who joined Sunderland from Irish club Cork City in 2008, is on loan at Championship side Hull City until the end of next month.
Sunderland, 17th on the table and one point above the relegation zone, face Chelsea on Saturday before matches against Reading and Manchester United.