FC Barcelona striker Samuel Eto'o is expected to be out of action for up to three months after tearing and displacing the meniscus of his right knee.
Eto'o was carried off on a stretcher after attempting a pass to Ronaldinho in the 65th minute of Barcelona's 1-1 draw on Wednesday at Werder Bremen in the Champions League.
The Cameroon striker was to undergo tests later Thursday to determine the full extent of his injury.
"This type of injury occurs with a sudden change in the direction of the knee," Barcelona doctor Ricard Pruna was quoted as saying on the club's Web site Thursday.
Eto'o, voted third in last year's FIFA world player of the year award, was making his 101st appearance for Barcelona. The 25-year-old, Africa's top player of the last three seasons, has scored 68 goals for the club, including 26 last season which made him the Spanish league's top scorer. He heads this season's chart with four.
The defending European and Spanish champion is second behind Chelsea in Champions League Group A. It lies top in the Spanish league with 10 points from four games.