Brighton midfielder Alan Navarro will miss the majority of the season after suffering a serious knee injury.
The 29-year-old damaged his cruciate ligament after catching his studs in the turf during Tuesday night's Carling Cup defeat at Northampton.
"It's a terrible blow for Alan," said Seagulls boss Gus Poyet.
"He is one of our key players and I felt he was in great form in recent weeks.
"He will come back, and he may still have a part to play at the end of this season, but for now he faces some serious surgery and a lot of hard work with the physios in terms of his rehabilitation."