Uncapped Ospreys flanker Jac Morgan will make his Wales debut against Scotland in the Six Nations as one of four changes made by coach Wayne Pivac.

The other changes see Ospreys duo Owen Watkin and Alex Cuthbert replace Josh Adams and Johnny McNicholl.

Adams is ruled out of Saturday's game in Cardiff with a tight calf.

Captain Dan Biggar will make his 100th international appearance while centre Jonathan Davies will achieve the same milestone if he comes off the bench.

Biggar will make his 97th Wales appearance to go alongside three Lions tests in South Africa in 2021, while Davies is in line to win his 94th Wales cap alongside his six Lions tests.

New boy

Morgan will be Wales' second new cap of the tournament following hooker Dewi Lake.

Former Wales Under-20 captain Morgan switched from Scarlets to Ospreys for the 2021-22 season and has been one of the form flankers in the Welsh domestic game.

The open-side will wear the number seven jersey with Basham switching to six and Moriarty packing down in between them and Wainwright dropping down to the bench.

Moriarty, 27, played his 50th international after coming off the bench in Dublin in what was only his second game since suffering a shoulder injury against New Zealand in October 2021.

Wales are currently without injured British and Irish Lions back rowers Justin Tipuric, Josh Navidi, Taulupe Faletau and Dan Lydiate.

"Jac comes in for his debut and is someone that's really impressed us in training," said Pivac.

"He's worked very hard, he gives us a lot of physicality and he's very good over the ball.

"With Ross [Moriarty] now having had more training and game time under his belt we think he's the right guy to start.

"On reflection, we didn't achieve what we wanted to out in Dublin.

"Part of it was getting parity in terms of the physical side of the game, we came up short and there is no hiding from that fact.

"Jac is a very abrasive sort of player, and Ross we know is very strong in that area. We've leant that way, and it gives us something different."

Centre conundrum

Pivac insists regular Cardiff wing Adams would have been in contention for another centre start if he was fit.

"It was a discussion we were having," added Pivac.

"There has been a lot of talk about that selection. When you break down the performance, we don't think that him playing at 13 was the cause for the tries they scored and he did a lot of good work.

"With his injury, if you are talking a World Cup and the knockout stage, you would probably give it a go, but it is one of those ones where we don't think it is worth the risk.

"If it does worsen, that would be him gone for the rest of the tournament and quite some time."

Following Adams' injury, Watkin is named at outside centre where he will partner Nick Tompkins with no room for Willis Halaholo who missed the opening defeat with a hamstring injury.

"Owen has gone away after being left out of a squad or two and has worked hard," added Pivac.

"He is keen gets an opportunity and in confident mood.

"With Willis, it is a matter of getting some volume into him and sharpness he needs to get back to play at Test level and he is heading in the right direction."

Cuthbert, who joined Ospreys from Exeter in the summer of 2021, will play his 50th international when he wins his 49th Wales cap to go alongside one Lions test appearance against Australia in 2013.

It will be his first Six Nations game in five years with his last tournament display coming against England in a 21-16 defeat in Cardiff in 2017.

The 31-year-old returned from the wilderness with a try-scoring appearance against Fiji in November 2021, but was not considered last weekend because of injury.

"He's big, strong and quick and a very good finisher, as we saw against Fiji," added Pivac.

"Hopefully, we get the ball in his hands a little bit more than we did last week."

Wales: L Williams; Cuthbert, Watkin, Tompkins, Rees-Zammit; Biggar (capt), T Williams; W Jones, Elias, Francis, Rowlands, Beard, Basham, Morgan, Moriarty.

Replacements: Lake, G Thomas, D Lewis, S Davies, Wainwright, G Davies, Sheedy, J Davies.