Sevilla will be without Germany midfielder Piotr Trochowski for up to eight months after he underwent knee surgery.
The Primera Division club confirmed that Trochowski, 28, had undergone surgery at the Vail Valley Medical Centre in the US to repair damaged cartilage in his right knee.
Scans showed he needed surgery after being injured during the first half of Sevilla's Primera Division defeat to Barcelona three weeks ago.
A statement on the Sevilla website read: "The operation has gone as planned and, if there are no complications, the recovery period is estimated at around eight months."
Trochowski will remain under observation in Vail Valley for a month before returning to Spain to continue his rehabilitation.
Information from the Press Association was used in this report