Lee Cattermole has made just two appearances in the Premier League this term, the second of which was on September 24 in a 3-2 home defeat to Crystal Palace.
The long-standing back injury that the 28-year-old aggravated in that loss had reportedly started to clear up as he neared a return.
But now the midfielder has torn cartilage in his hip and is expected to be out until March, robbing Sunderland of his his experience of previous relegation battles as David Moyes’ side head towards another fight for survival.
Moyes told a media conference on Friday: “Lee Cattermole had an operation in America on Monday on a torn cartilage in his hip and will be out for four months.
“He’s out there just now, coming back in the next day or two, I think.”