Chelsea midfielder Oriol Romeu will be out for six months after having knee surgery.
The 21-year-old Romeu was taken off after 20 minutes in Chelsea's 3-1 victory over Sunderland on Saturday after injuring his right knee.
He underwent surgery on Monday on his anterior cruciate ligament and medial meniscus, the club said.
Romeu has made nine appearances for Chelsea this season, and 33 since joining from Barcelona in the 2011 off-season.
His place in Chelsea's Club World Cup squad has been taken by George Saville.