The 27-year-old suffered a knee injury in the Pro14 against Benetton on 15 September and will be out for up to four months.

Scarlets head coach Wayne Pivac said: "He's ruptured his PCL [posterior cruciate ligament] so I don't think you'll see him this side of Christmas."

Scarlets' back-rowers Will Boyde and Josh Macleod are also injured.

Davies will miss Wales' autumn Tests against Scotland, Australia, Tonga and South Africa, played on successive Saturdays from 3 November.

The Olympic Sevens silver medallist won his first cap against Italy in the Six Nations in March 2018 and produced two-man-of-the-match performances in the summer tour matches against Argentina.

"It's a massive blow to lose James, especially with another two sevens out, it puts a real strain on the team," said Pivac.

"He's a quality player, everyone knows that. He's a big part of how we play the game.

"He's become a leader in the group. He was stepping up nicely in that classroom role and as a senior player in the group. He'll be sorely missed but it's just one of those things. We can't do anything about injury."

Scarlets worries

Lewis Rawlins was at open-side in last weekend's defeat at Connacht as Pivac juggled his depleted resources.

Dan Davis will wear the seven jersey in the Pro14 match against Southern Kings this Saturday while Boyde and Macleod could be fit for the derby against Ospreys on 6 October.

Pivac says the absences of Davies, Boyde and Macleod have affected a style of play that relies on turnover possession to launch attacks. Davies, in particular, has built a reputation around such work in the tackle area.

"Those players [Boyde and Macleod] have both played seven and eight for us and have been coming along in their careers nicely, so to lose all three of them has made it a little bit difficult," said Pivac.

"On the weekend we found that one of the things we weren't able to do was slow the ball down at the breakdown and we knew that would possibly be the case so we tried to bring more line speed and get turnovers that way.

"We got a few that way. It's just part of the possession stakes that we normally rely on and we're very good playing off turnover ball.

"We don't have that luxury at the moment so we're just having to work around that."

Pivac says the Scarlets will consider making a short-term flanker signing if their injuries continue with Scotland's John Hardie being linked.

Good news for one family member

However, Davies' Wales and British and Irish Lions centre brother Jonathan is set to return from a hamstring injury against Southern Kings in Llanelli on Saturday.

Jonathan Davies suffered the injury in the warm-up for their opening Pro14 game against Ulster.

But fellow Wales internationals Ken Owens, Leigh Halfpenny and Gareth Davies not being considered to face the South African team.

Scrum-half Davies and full-back Halfpenny's absences are because they are being managed under National Dual Contracts, while hooker Owens is being rested.