Lille captain Rio Mavuba has undergone surgery on a knee injury and faces between six weeks and three months on the sidelines.
Last week, the club's coach, Rudi Garcia, confirmed that Mavuba - whose injury ruled him out of France's squad for the World Cup qualifier in Spain - would be operated on after suffering the injury during Lille's 2-0 Ligue 1 defeat against Rennes.
Lille are struggling in both Ligue 1 and the Champions League, in which they are bottom of Group F after losing to BATE Borisov and Valencia.
But Mavuba is hopeful of a smooth recovery after the operation on his left knee and has begun rehabilitation at Lille's Luchin training centre.
The worst case scenario would be that Mavuba is out of action until the winter break, but he said: "I tell myself that I'll come back stronger and fresher," before the surgery.