Jamie Roberts believes Warren Gatland's return as head coach is a "huge shot in the arm" for Welsh rugby.

However, Tom Shanklin - who also played under Gatland - has warned naming the right back-up team will be crucial.

Gatland, 59, will take charge for next year's Six Nations and Rugby World Cup after replacing Wayne Pivac.

Gatland is Wales' most successful and longest-serving coach, having won three Grand Slams during his previous 12-year reign. He also guided Wales to the semi-finals of the 2011 and 2019 World Cups.

Roberts won 94 caps for Wales and featured in the memorable 2008 and 2012 Welsh Grand Slam successes under Gatland.

He was also handed his third Lions cap by the New Zealander, starting the decisive third Test in the winning 2013 series against Australia.

Roberts believes Gatland's return will galvanise a Wales team - who won just three games in 2022 - ahead of the Six Nations, which starts against Ireland in Cardiff on 4 February, 2023.

"He's a reputable coach, a lot of experience, knows the game in Wales inside out. It will give the lads a boost, there is no doubt about that," Roberts told the BBC's Rugby Union Weekly podcast.

"With change often comes a lift. New coach, new people to impress - those lads will be coming into the squad desperately hungry to prove their worth and this guy has a win percentage ratio of over 70% in the Six Nations."

Welsh Rugby Union chief executive Steve Phillips described the decision to replace Pivac just 10 months before a World Cup as "one of the toughest calls to make in sport", but one taken "in the very best interests of our national team".

Phillips called replacement Gatland as "one of the very best coaches", adding: "He will undoubtedly be able to make an immediate impact, just as he did when he joined us for the first time in 2008."

In his first spell as Wales coach, Gatland won his first game in charge, a shock victory against England at Twickenham. His side famously went on to win the Grand Slam in a Six Nations campaign which saw Roberts make his international debut.

The now-retired centre believes Gatland will be well aware of the pressure for another swift turn around in fortunes.

"Warren knows this is a results business and there'll be a huge amount of pressure on him, but from where Wales are at the minute you'd like to think the only way is up," added Roberts.

"We've had one of our worst years on record in the professional era. Three wins from 12. We've lost to Italy and Georgia at home for the first time in our history.

"I think Warren understands that. He knows the only way is up for this group of players and there's a huge amount of upside to come in Welsh rugby.

"He knows how to win in the northern hemisphere at Test level and it's not just his coaching nous that he can add to the game at Test level in Wales, but his experience across the whole board. Hopefully that will help in delivering performances for our clubs as well.

"I think it is a huge shot in the arm for Welsh rugby. There will be a lot of fans who think potentially it is a step backwards, but it is a step backwards to take three or four steps forwards."

Tough job

Wales' poor performance in the international arena since their 2021 Six Nations title is set against the back-drop of turmoil in Welsh domestic rugby.

Disappointing results for the four Welsh regions - Cardiff, Dragons, Ospreys and Scarlets - have been accompanied by difficulties in securing a funding model for the game in Wales, with warnings from the players association about its members "reluctantly seeking security elsewhere" and fears for the grass-roots game in Wales.

Roberts' former team-mate and fellow centre Shanklin agrees Gatland's appointment only deals with one issue facing the game in Wales.

"It's everything," said Shanklin. "It's the governance of Welsh rugby, its who's in charge, how decisions are put through.

"It's about player development, it's about not losing players in the system, it's about academies producing better players, it's about grass-roots.

"It's not just about the Welsh team, it's about the whole of Welsh rugby."

Shanklin also feels appointing the right coaching team will be vital to Gatland's chances of another successful spell.

"The job he has got on his hands is a lot tougher than when he took over in 2008," said Shanklin.

"Being a head coach and a figurehead of Welsh international rugby is massive, but it's the coaches that he is going to have around him which I think is going to be just as key."

A major part of Gatland's set-up during his previous stint with Wales was defence coach Shaun Edwards, who is now under contract with the French Rugby Union.

Current attack coach Stephen Jones was brought in by Gatland for the 2019 World Cup, where Wales bowed out in the semi-final to end Gatland's first spell in charge.

"I thought what Warren Gatland did for 12 years as Welsh coach, the Grand Slams, the titles, the semi-final of the World Cup in 2019, I thought he left at the perfect time for Wales. I thought he took Wales as far as he could," added Shanklin.

"It does surprise me a little bit that he has come back because the job he has on his hands is a lot tougher.

"In 2008 he inherited a load of really good world-class internationals and he had them for 10 years. Now there's a bit of a change of the guard.

"There's a new cycle of players coming in so it's going to be a lot tougher, but Gatland's done nearly everything there is to do in northern hemisphere rugby so he knows the challenges that are ahead of him and he's confident that he can make a change.

"There's no doubt that change had to be made, with Wayne Pivac leaving.

"I have to say that the way Wayne Pivac has handled himself over this last week or two has been amazing."

Gatland's magic touch

Former Wales forward Ian Gough had been in favour of allowing Pivac to stay in charge until the 2023 Rugby World Cup.

However, following the coaching change, ex-Ospreys lock Gough said Gatland made an "environmental change" in the Wales team's training during his time with the national squad.

"The standards went just through the roof because you weren't allow to drop your standards," said Gough.

"He set the bar high very quickly and you realised that if you fell off that tightrope, then you were gone.

"Over his career you saw the likes of Ryan Jones being dropped as captain and Mike Phillips and Adam Jones, Richard Hibbard, these quality British Lions players, when he didn't see enough in them any more, they were gone.

"He's just got that magic touch. He's on the pulse of what makes this Welsh team work.

"He's very good at building players up and getting them to believe in themselves and getting them to believe they are good enough and can compete with the best in the world."