Sunderland midfielder Claudio Reyna has been ruled out for six months with a cruciate ligament injury.
Scans confirmed the extent of the injury, which the US international midfielder sustained during Monday's 1-1 draw with Bolton at the Reebok Stadium.
The player (29) needs an operation - but surgery cannot be carried out until the swelling has settled, so it is pencilled in for between two and three weeks' time in Los Angeles.
The news adds to the worries of new Black Cats boss Howard Wilkinson, who is facing up to an injury crisis just weeks after taking over the Barclaycard Premiership strugglers.
Reyna joins goalkeepers Thomas Sorensen and Thomas Myhre and midfielder Jason McAteer on the Stadium of Light injury list.
Wilkinson said: "It's always a big blow to lose good players but unfortunately that's life. Claudio's problem is someone else's opportunity. His credentials are there for all to see but for the immediate and mid-term future he will not be available, and that's a blow".