Wales coach Wayne Pivac has made six changes for Saturday’s rearranged Six Nations clash with Scotland at Parc y Scarlets.

In come Liam Williams, Owen Watkin, Gareth Davies, Tomas Francis, Will Rowlands and the uncapped Shane Lewis-Hughes.

Having correctly predicted the changes, rugby correspondent Simon Thomas now explains the thinking behind them.

15. Leigh Halfpenny

The fit-again Liam Williams could have returned in his Lions Test spot of full-back, but Halfpenny has been in fine form of late and didn’t deserve to lose his place.

With heavy rain forecast, there’s likely to be a fair bit of kicking, so his consummate positional play and reliability under the high ball will be priceless.

He also provides defensive steel, determined running and a world-class place-kicking option should Dan Biggar have another off day in front of the posts as he did in Paris.

14. Liam Willliams

Sanjay has had precious little game-time, with just one outing since March due to a foot injury, but he did look sharp on his return for the Scarlets against Benetton last weekend and has clearly done enough both there and in training to convince the coaches he is ready.

Out in Treviso, he countered from deep to good effect on a couple of occasions and there could well be opportunities to show that trademark strength to his game on Saturday with a fair bit of kicking likely.

There’s no doubting his class and to bring that back on board something had to give, with George North the man to miss out, dropping from the 23 altogether, with Pivac saying he has things to work on.

A lot of people would have liked to see Louis Rees-Zammit involved, but he is out of the equation due to a shin problem, so the back three cover will presumably be provided by Rhys Patchell, who can go to full-back if a reshuffle is required.

13. Jonathan Davies

The 2017 Lions Man of the Series in New Zealand made an immediate impact on his Test comeback against France last weekend, crashing up the middle to suck in two defenders ahead of Halfpenny’s opening minute try.

After that, he had a relatively quiet game by his standards, with five carries and six tackles in total, but he will have benefitted from the run-out after close on a year out of the international arena and was always going to keep his spot, such are the lines he hits and the defensive organisation he brings.

12. Owen Watkin

Owen Watkin replaces Nick Tompkins

It will be a first Test start for Watkin since the World Cup third-place play-off against New Zealand almost exactly a year ago, with injury having kept him out of the first chunk of the Six Nations.

Nick Tompkins picked up a dead leg in Paris, but has been back in training and is on the bench, so this is a selection call, with the Dragons man not having his best game against the French.

The direct, hard-running Watkin will provide the kind of go-forward that was missing last weekend, while also stiffening the midfield defence, with Pivac today acknowledging there were a couple of errors there.

11. Josh Adams

Has established himself as one of the first names on the team-mate when fit with his try-scoring exploits and all-round excellence over the last couple of years.

Wales will want to get him on the ball more against the Scots, so he can show the attacking threat that has been so evident with his outstanding form for Cardiff Blues of late.

He completes a real quality back three.

10. Dan Biggar

When things don’t click for Wales and they lack a cutting edge, the focus often turns to the 10 and you’ve seen calls for a more attack-minded option in Rhys Patchell or even the uncapped but in-form Callum Sheedy.

But with win at all costs being the theme, the pragmatism and tactical control of Dan Biggar was always likely to get the nod, particularly with his ability to navigate the ship through the literal and metaphorical storm, while the man is a born fighter made for under-pressure situations.

Having uncharacteristically missed three shots at goal in Paris, he will want to put things right on that front, especially with some advocating a switch to the boot of Halfpenny.

9. Gareth Davies

It’s been a switchback ride at scrum-half so far during Pivac’s tenure, with the role rotating between Davies, Tomos Williams and Rhys Webb.

With Williams crocked and Webb having taken a bang to the knee against France, it’s now back to Davies.

He will add a bit more physicality around the fringes and a forceful running threat, while his roving role in defence, flying up to apply pressure and hunt out intercepts, has been a big weapon over the last year or so.

The experience of Lloyd Williams sees him leapfrog Kieran Hardy in the pecking order to provide a seasoned tactical presence on the bench, following his recent call-up to the squad, with his box-kicking accuracy made for wet weather rugby.

Pivac has today revealed it wasn't the plan to play Hardy in the first two games of the autumn and they have stuck to that, describing him as one for the future.

1. Rhys Carre

There’s real competition at loosehead, with Wyn Jones and Nicky Smith within the squad and Rob Evans now back from neck surgery.

But Pivac has stuck with the youthful promise of Carre and will be hoping to see him make a real impact with ball in hand to provide more carrying oomph up front, while also continuing the solid scrummaging he showed in Paris.

Wyn Jones, now fully recovered from a tight hamstring, takes over from last weekend’s try-scorer Smith as the option off the bench.

2. Ryan Elias

There was an argument for starting with Sam Parry as he is so effective over the ball and the more jackals the better in the modern-game, especially with Wales having struggled at the breakdown against the French.

But Elias gets another chance to show he is the man to step into the shoes of the sidelined Ken Owens. As with Carre, the hope will be that he too can show his worth in the loose as a carrier, while doing the bread and butter basics at the set-piece.

3. Tomas Francis

Samson Lee made a solid return in Paris on his first Wales appearance in 14 months, shoring up the scrum, only then to be forced off after taking a bang to the head, which has kept him out of this game.

Meanwhile, Francis has come back into the mix having been away on Premiership final duty with Exeter last weekend.

He had been Wales’ first-choice tighthead for a couple of years before suffering a shoulder injury in the World Cup semi-final against South Africa and now resumes his scrum cornerstone role, with Dillon Lewis able to come on and make an impact both with ball in hand and as a jackal when the game loosens up.

4. Will Rowlands

Will Rowlands, left, takes over from Cory Hill, right, in the second row

There has been much talk about the need to add physicality to the pack post-Paris and the 6ft 8ins, 19st 5lb Rowlands will certainly provide a presence as he makes his first start for Wales.

He also delivers a huge work rate, with a big tackle count and forceful carrying, while he’s got a turn of pace for a big man, offering mobility and agility, in addition to being a reliable lineout operator.

The 29-year-old, who replaces the benched Cory Hill, comes oven-ready from top-level club rugby having just played for Wasps in the Premiership final.

5. Alun Wyn Jones

What can you say about the great man that hasn’t been said already?

It will be a landmark occasion for him on Saturday when he leads Wales out against Scotland to become the most-capped player of all time, surpassing the great Richie McCaw.

But as he makes his record-breaking 149th Test appearance, his sole concern will be helping his team end their four-match losing run.

For him, it’s always been about the collective rather than personal glory.

6. Shane Lewis-Hughes

The headline news in the team selection.

Not named in the original autumn squad, the uncapped Lewis-Hughes has leapt straight into the starting line-up in place of Aaron Wainwright, having impressed in training to back up his outstanding form with Cardiff Blues.

So what does he bring to the party? Well, his motto is “obsessed to be the best” and that sums up his total commitment and steely-eyed focus.

He is an absolute machine in terms of his tackle count, with echoes of Dan Lydiate at his best, while he will add an edge and a physicality that was lacking in Paris.

A fired-up Shane Lewis Hughes on duty for Cardiff Blues

At 6ft 4ins and 17st 11lbs, he can also carry hard, while he’s effective over the ball and is an excellent lineout option.

With Josh Navidi, Ross Moriarty and Josh Macleod all sidelined from the original squad, it’s a huge opportunity for the 23-year-old from Ferndale.

7. Justin Tipuric

To my mind, the Ospreys openside is always at his most effective when he has someone doing the unseen hard graft on the other flank, with Josh Navidi having filled that role perfectly, enabling Tipuric to excel in the wider channels with his footballing ability.

In Lewis-Hughes, he has another physical workhorse at 6, so it’s a combination that could reap rewards.

It will certainly give Wales a real defensive double act, with Tipuric having topped the tackle count in Paris, while it will hopefully provide him with more opportunities to do what he did in the opening minute against France, with his sublime miss-pass having paved the way for Halfpenny crossing.

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8. Taulupe Faletau

Having for so long been one of the absolute certain selections in the Wales team, Faletau now finds himself in a different situation.

He spent two years out of the side through injury and, since returning, he hasn’t quite been able to make the same kind of impact as of old, when he used to regularly top the various stats charts.

Were Moriarty or Navidi available, he might not be starting at No 8 this weekend, but if ever there was a case where you hope class really is permanent than this is it.

To see Faletau firing again and showing that class would be such a timely boost.

Should Wales look to change things up in the back row at some point, James Davies can come off the bench to seek out those turnovers.