Defending champions Wales will be without Jonathan Davies for the Six Nations.
He's out for six months with a knee injury sustained in their win over Fiji at the Rugby World Cup.
Davies' Scarlets teammate Rhys Patchell also needs surgery on a shoulder issue which he picked up in the third-place playoff and will need 16 weeks to recover.
"Rhys Patchell and Jonathan Davies both face surgery following injuries sustained in the recent Rugby World Cup," Scarlets and the WRU confirmed in a joint-statement.
"Rhys Patchell is expected to return to play between 12-16 weeks following a shoulder injury, whereas Jonathan Davies faces at least six months recovering from knee surgery."
While Warren Gatland has ruled himself out of the race to become New Zealand's next head-coach.
The former Wales boss says he's declined an invitation to apply to become Steve Hansen's successor as he's already committed to coaching the Lions next year.
Gatland has also joined Super Rugby franchise The Chiefs after his 11-year spell with Wales:
"I was asked to apply for the position and I've gone back to them to say I won't be putting my name forward, because at this point I've made a commitment to the Chiefs and I've made a commitment to the Lions.
"They appreciated it, they understood it...I just think it would look poor me applying. It wouldn't sit well with me, having already made those commitments to the other two."
