Sunderland striker Fraizer Campbell could miss much of the 2011/2012 season if he needs a second knee operation.
The former Manchester United striker damaged his cruciate ligament in August last year and hasn't played since.
He twisted his knee ahead of the 5-0 defeat by Manchester City and may have to go under the knife once again.
Sunderland manager Steve Bruce said: "We do fear that he might need another operation and that could rule him out for the best part of next season."
"We think the surgeon needs to go and have a look inside his knee again and if it does need repairing again, then Fraizer is going to miss the best part of next season as well, which is an even worse blow for us and more importantly, for the kid," Bruce continued.
"Nobody could have done his rehabilitation better than he did but he fell over and twisted it on the Friday before we played Manchester City," he added.
Campbell's last appearance for the Black Cats was in the 1-0 win over - ironically - Manchester City last August.
Ahead of Saturday's crucial trip to Birmingham, Bruce has only two fit strikers in Asamoah Gyan and Danny Welbeck, who has himself only just returned from a knee injury.
Meanwhile Black Cats defender Titus Bramble has been told that he is unlikely to play again this season.
The 29-year-old former Ipswich, Newcastle and Wigan player has failed to recover from knee cartilage damage which has sidelined him for the last 2 games, but it's not thought that he needs an operation.
Bramble said on his Twitter account: ""Just been told that I'm unlikely to play again this season. I don't need an operation, so that's a bonus.
"Will work hard and make sure I'm right for the start of next season," he added.
http://news.bbc.co.uk/sport2/hi/football/teams/s/sunderland/9458978.stm
