Sunderland will be without Jan Kirchhoff for another three months after he underwent knee surgery.
The midfielder suffered an injury in his side's 1-0 defeat to Chelsea on December 14 and missed last Saturday's 1-0 win over Watford.
Manager David Moyes has now confirmed Kirchhoff will be missing for up to 12 weeks, a major blow in Sunderland's battle against Premier League relegation.
"Jan had an operation during the week to repair his lateral meniscus," Moyes said ahead of the Boxing Day away match against Manchester United.
"At the moment we think it will be close to 12 weeks.