The Brazilian has already been absent from the Blues' last two Premier League fixtures against Fulham and Sunderland because of the problem, although he had linked up with Brazil for their midweek friendly in Qatar. A statement on the club's website read: "Further to the Chelsea medical team's diagnosis, the Brazilian national team doctors agree that further investigation via arthroscopic surgery is required on the player's right knee. That will take place over the coming days. "He is expected to be out for approximately six to eight weeks." With defensive partner John Terry also out with injury at the moment, 28-year-old's extended absence is a further blow to manager Carlo Ancelotti. In July Alex suffered a thigh injury which made him a doubt for the start of the new season, but he did feature in the club's 6-0 thumping of West Brom on August 14. Club captain Terry is undergoing treatment to resolve a problem with a nerve in his leg.
