Cardiff Blues and Wales star Sam Warburton is to undergo surgery following the recurrence of a long-standing neck injury.
The Blues said that former Wales skipper Warburton, who captained the British and Irish Lions in New Zealand this summer, faces up to four months out.
It means that Warburton will miss Wales' autumn Tests against Australia, Georgia, New Zealand and South Africa.
Sam Warburton has beaten his ankle injury and will captain the British and Irish Lions against the Highlanders on Tuesday, the team have announced.
The Wales flanker missed the 12-3 win over the Crusaders but has made a full recovery - and now has the chance to prove his form and fitness for the first All Blacks Test on June 24.
Ireland's Jared Payne has shaken off a calf issue to start at full-back, while Wales' Dan Biggar has beaten a head injury to feature at fly-half.
British and Irish Lions team to face the Highlanders on Tuesday:
J Payne (Ireland), J Nowell, J Joseph (both England), R Henshaw (Ireland), T Seymour (Scotland), D Biggar, R Webb (both Wales), J Marler (England), R Best (Ireland), K Sinckler, C Lawes (both England), I Henderson (Ireland), J Haskell (England), S Warburton (Wales, capt), CJ Stander (Ireland).
Replacements: K Owens (Wales), J McGrath (Ireland), D Cole (England), A W Jones, J Tipuric (both Wales), G Laidlaw (Scotland), O Farrell, E Daly (both England).
Sam Warburton could enter Wales' autumn series without having played a game since undergoing surgery to repair a fractured cheekbone sustained three weeks ago.
The Blues flanker will miss Friday night's Challenge Cup clash with Pau in Cardiff due to neck stiffness, leaving him short of match fitness ahead of captaining Wales against Australia on November 5.
Only one Guinness Pro 12 fixture remains before the Wallabies visit Principality Stadium - against the Scarlets on Friday week - and he is unlikely to be risked in that with four autumn internationals looming.
The British and Irish Lions skipper had a metal plate inserted into his cheekbone to repair the injury suffered against Leinster on October 1 and while the operation was a success, his comeback has been delayed.
A Blues statement read: "Sam Warburton was not considered for selection as a precaution after experiencing some residual stiffness in his neck, but has fully recovered from surgery on a fractured cheekbone."
Sam Warburton requires surgery on his fractured cheekbone but is still expected to feature in all four of Wales' autumn internationals.
Warburton clashed heads with Josh van der Flier in Cardiff Blues' 16-13 defeat by Leinster on Saturday and has been told by a specialist he will be sidelined for no more than a month.
"Warburton will have a small plate inserted in his cheekbone. It is estimated he will be out of action for approximately two to four weeks," a Blues statement read.
Wales captain Sam Warburton is set to undergo scans to determine the extent of his suspected fractured cheekbone.
Warburton was replaced early in Cardiff's 16-13 defeat to Leinster on Saturday as the Blues suffered their first Guinness PRO12 loss of the season.
The flanker, 28 on Wednesday, has already seen a specialist to assess the injury, which Cardiff Blues hope is not too serious.
It could be that Warburton has fractured a small bone in his cheek, but the scans will show the damage.
Wales' first match of the Autumn Test series is against Australia on November 5. Argentina, Japan and South Africa follow in successive weeks.
A Plaid Cymru MP has attempted to play down a row over Wales rugby captain Sam Warburton after he criticised him for suggesting that he felt British, rather than Welsh.
The Lions captain's comments was responding to claims by an England wing that Wales players "hate England".
Jonathan Edwards yesterday tweeted:
He has now clarified his point:
He also issued a statement saying: "Let's be clear I am not attacking any individual over their identity.
"I would hope that the captain of Wales would feel Welsh. Of course lots of people feel both Welsh and British."
More than a third of this summer's British and Irish Lions tour squad is expected to be provided by Wales.
The 38-man group for Australia will be unveiled today, with Sam Warburton the favourite for the Lions captaincy, aged 24, he could become Wales' youngest Lions tour captain.
Warburton has already led Wales to a World Cup semi-final in 2011, and a Six Nations title and Grand Slam last season.
At least 14 of his countrymen could join him, with Ireland likely to provide the second biggest number, followed by England and then Scotland.