Sam Warburton: Lions captain out of Six Nations after knee surgery
British and Irish Lions captain Sam Warburton will miss Wales' 2018 Six Nations campaign after having knee surgery.
The 29-year-old flanker, who also has a neck injury, will be out for between four and six months, according to the Welsh Rugby Union (WRU).
"In consultation with the WRU and Cardiff Blues we decided it would be proactive to have surgery," he said.
The operation was to correct an existing problem, not a new injury.
The recovery period is likely to mean Warburton will not play a game for region or country this season.
He captained the Lions on their 2013 tour to Australia, when they won the series 2-1, and on the drawn series against New Zealand this year.
Warburton has not played since the third Test in Auckland in July, missing the whole of Wales' autumn Test series.
His injury means Wales are already without two frontline players for the Six Nations, which they begin on 3 February with a home game against Scotland.
Centre Jonathan Davies - the Lions' man of the series in New Zealand - is out for the season after surgery on an injured ankle suffered playing for Wales against Australia on 11 November.
Second row Jake Ball has had surgery on a dislocated shoulder and is unlikely to be available for the start of the tournament.
Warburton's career has been punctuated by injuries, with his place on the 2017 Lions tour in jeopardy until the last minute because of a knee injury suffered playing for Cardiff Blues in April.
He is employed jointly by the Blues and the WRU, which pays 60% of his national dual contract.
In addition to his two stints as Lions captain, Warburton has led Wales on a record 48 occasions, though relinquished the captaincy to Alun Wyn Jones in January.
A statement by the WRU said the surgery was to ensure Warburton would be fully fit on his return.