The Cardiff Blues flanker, who led the British & Irish Lions to a drawn Test series with New Zealand in the summer, exacerbated the injury in training this week and will now miss the Under Armour autumn series where Warren Gatland’s men take on Australia, Georgia, New Zealand and South Africa.
“It’s a major blow for all concerned – Sam, the Blues and Wales. He thought that after a two month break he would come back really fresh and we all hoped he would be back playing this month,” said Blues head coach Danny Wilson.
“It is a long-standing issue that causes him pain and discomfort on and off. The feeling was that the eight weeks he had off after the Lions tour would give it time to settle.
“He came back into training last week feeling confident about it, but the injury flared up again as he was going through some contact training on the tackle pads. We looked into it in more detail and it has let to where we are now.
“Sam is obviously extremely frustrated and it means we now have three openside flankers at the Blues who are ruled out for up to four months at the same time – Sam, Ellis Jenkins and Jim Botham.
“Sam has undergone scans and has been reviewed by a consultant, who confirmed the management plan. It’s the right thing for him to do and Sam is a very good professional when it comes to rehabbing injuries.”