Brighton and Hove Albion midfielder Andrew Crofts is out for the rest of the season.
The 30-year-old suffered a serious knee injury in the draw at Watford last Saturday (4 October).
Crofts, a Wales international, had MRI scans and exploratory surgery in London yesterday (Wednesday 8 October).
Surgeons found that he had suffered a partial tear of his anterior cruciate ligament and a tear to the meniscus.
The club said: “Successful reconstructive surgery has taken place and Crofts is now recovering in hospital. He is expected to be out of action for the remainder of the season.”
He ruptured his cruciate ligament at home to Birmingham City in January and missed the rest of last season as a result.
Manager Sami Hyypia said: “We are all devastated for Crofty. He is an important member of our squad and worked incredibly hard to get back to full fitness after last season’s knee injury.
“Crofty is a very strong character and he will continue to receive the best possible care and treatment from our medical staff throughout his rehabilitation.
“In the meantime, everyone at the club wishes Crofty well for a full and speedy recovery.”