LONDON: Chelsea captain John Terry will undergo knee surgery and be out for up to six weeks, dealing a further blow to the team's faltering season but relieving England of a potential selection headache.

Terry has not played for more than three weeks and Chelsea's medical team decided on Tuesday that the defender must have an operation on his right knee.

The center back trained Monday in Italy on the eve of Chelsea's Champions League match against Napoli but woke up in discomfort a day later.

"John has tried hard to be ready for tonight's game but it was clear after training last night that it was not going to be possible," Chelsea said in a statement. "He will undergo an exploratory arthroscopy in the next day or so, after which the club's medical team will be better placed to advise on a prognosis."

Coach Andre Villas-Boas said Terry will be out for up to six weeks.

The injury saves interim England coach Stuart Pearce from having to decide whether to select Terry and Rio Ferdinand in the squad for next Wednesday's friendly against the Netherlands.

Terry was stripped of the England captaincy earlier this month due to his upcoming trial for allegedly racially abusing Ferdinand's brother, Queens Park Rangers defender Anton Ferdinand.

Fabio Capello quit as England coach after the Football Association stripped Terry of the captaincy without consulting the Italian.

Terry's absence will be less of a blow for England than Chelsea, which hasn't won a game since he last played on Jan. 28 against QPR. Chelsea has slipped to fifth in the Premier League and drew against Birmingham in the fifth round of the FA Cup on Saturday.

The 31-year-old Terry has been troubled by the knee injury since colliding with a post last month in the FA Cup against Portsmouth.