England captain Michael Vaughan will take no part in the winter Ashes series in Australia, it has been confirmed.
Vaughan's leadership and batting will be badly missed this winter
Vaughan underwent an operation on his right knee earlier this week which revealed more damage than expected.
The England and Wales Cricket Board says he will be targeting a return to cricket early in 2007 "with a view to being available for the World Cup."
The 31-year-old has been told that a slow rehabilitation will give the surgery the best chance of success.
Australian batsman Justin Langer told BBC Sport: "I'm disappointed for him. You never like to see a fellow player out for any period of time with an injury.
"From an Australian point of view, I'm sure there'll be some advantage from him not playing in the Ashes.
"The reality is that if you take one of the best players out of any team it's going to have an impact. He's certainly one of those, he's the leader and a very good top order batsman as well."
England's selectors have already said Andrew Flintoff will lead the side in Australia this winter in the absence of Vaughan, who has not played for England since being forced to return home early from the tour to India.
But chairman of selectors David Graveney stressed Vaughan's long-term future was not in doubt.
"There is no suggestion that Michael Vaughan's career is under threat," he told BBC Radio Five Live.
Vaughan recently played a handful of matches for his county side, Yorkshire, but experienced soreness in his knee during a Championship match against Sussex at Arundel.
A meeting between Vaughan and the England and Yorkshire physios followed and it was decided that undergoing surgery for the fourth time in his career was the best option.
BBC Five Live reporter Pat Murphy said Vaughan would now face a "long and testing period of rehabilitation".
And he added: "There must now be genuine concerns over whether Michael Vaughan will play cricket again."
1999 Misses 3rd Test in South Africa with finger injury
2000 Misses home series against Zimbabwe with broken finger
2000 Strains calf muscle during tour to Pakistan
2001 Misses home Ashes series after surgery on left knee
2004 Misses first Test against New Zealand after twisting left knee
2005 Twists right knee while running between wickets in Pakistan and misses opening Test
March 2006 Flies home from tour to India after recurrence of knee trouble
June 2006 Decides to undergo further surgery on knee
Vaughan has played 64 Tests and 74 one-day internationals for England since making his debut on the 1999-2000 tour to South Africa.
He was appointed captain three years ago and has presided over one of the national team's most successful periods of the modern era.
England won seven of the 10 Test series played under Vaughan and famously recovered the Ashes from Australia after 16 years with a 2-1 victory last summer which enthralled the entire nation and earned him an OBE in the New Year's Honours list.
Since then, however, England have been beset by injuries to key players.
Pace bowler Simon Jones has undergone keyhole surgery on his left knee and although he refuses to rule himself out of the Ashes re-match this winter, it could be touch and go as to whether he makes it onto the plane.
Spinner Ashley Giles, meanwhile, has had two operations to try and cure a hip problem and does not yet know when he will be fit to return to action.