The 28-year-old midfielder, who has made just three appearances to date this season, had a procedure to repair a torn cartilage in his hip on Monday and now faces a long haul back to fitness.
Manager David Moyes said: "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."
The news came as a significant blow to Moyes, who has been without one of the club's most consistent performers in recent seasons for much of his reign on Wearside.
The setback arrived after a lengthy treatment process which eventually got to the root of the problem.
Moyes said: "It's a big blow because we have had hernias, we have had epidurals, we have had other things done but, by all accounts, we have found a tear in his cartilage in his hip which has now been repaired."
Cattermole, who joined the Black Cats in a £6million switch from Wigan during the summer of 2009, has been a key figure in the club's successful survival fights over the last four years.
But he was last able to take to the field for the 3-2 Premier League defeat by Crystal Palace on September 24.
Source : PA
Source: PA