The Cardiff Blues have today released a statement declaring that their back-row star is facing up to four months on the sideline.
Cardiff Blues confirmed on Tuesday Warburton is set to undergo a procedure to fix a "long-standing" issue.
He has yet to make an appearance this season after a post-Lions break.
The Blues said that Warburton had "exacerbated" the injury in training this week.
The British and Irish Lions captain exacerbated the problem on his return to training this week and inspection of scans revealed that an operation is required.
This comes as a major blow to both the Blues and Wales. Wales face Australia in Cardiff on 11 November, before home internationals Georgia and New Zealand precede their final Test of 2017, against South Africa on 2 December.
'It is likely that Sam will miss a period of up to four months'.
It means Warburton willmiss the first half of the Guinness Pro14 campaign, the Challenge Cup pool stages and Wales' November global fixtures against Australia, Georgia, New Zealand and South Africa.
Had he been fit, Warburton would likely have been a mainstay of Wales coach Warren Gatland's side for the November and December Tests.
Warburton has been capped 74 times by Wales and skippered the Lions on their last two tours.
The current recovery timescale, though, indicates that Warburton will be available for Wales' Six Nations campaign this season, which they kick off against Scotland on February 3.
But Warburton's absence is another blow to Cardiff, who recently saw fellow flanker Ellis Jenkins sidelined for up to 12 weeks with a hamstring injury.