Nuuausala will add size and experience to the Raiders forward pack when he makes his debut in Sunday night's season opener against the Cronulla Sharks at Remondis Stadium.

The 28-year-old New Zealand international was granted a release from the final year of his contract with the Roosters at the end of last season to sign a three-year deal with the Raiders.

Raised in Auckland, Nuuausala admits he struggled to make the transition to life in Sydney and arrived for the start of the 2008 season overweight and weighing up his future in the game.

Fitzgibbon took Nuuausala under his wing and showed him what was required to become a professional rugby league player.

"We could see the potential in him and it was pretty obvious he was a talented kid," Fitzgibbon said.

"He was a bit overweight and struggling and grappling with the fact he was a long way from home and learning how to live as a professional footy player.

"He was a really valued opinion among our guys, too, so everybody respects him at the Roosters.

"It was very tough to go for him and ourselves to see him leave and he was a really high valued clubman.

"He left an impression on us and I think the leadership role will suit him, with the opportunity to grow and to improve himself again.

"That's what he hungers for and I think he'll be great in that role down there.

"I'm sure he's going to be a really valuable buy for the Raiders."

Nuuausala was appointed as part of the Raiders' new-look leadership group alongside fellow recruits Sia Soliola and Josh Hodgson, Shaun Fensom and captain Jarrod Croker.

He played all of his 152 NRL games with the Roosters after debuting in 2007 and was a part of the club's premiership winning team in 2013.

Nuuausala credits Fitzgibbon with turning his career around and refers to him as "one of my older brothers".

"Without him, I don't think I'd be in this position right now playing first-grade for the Roosters or coming to Canberra," Nuuausala said.

"It didn't click until Craig Fitzgibbon helped me along the way.

"In 2008, I was overweight and he pulled me aside and said 'follow me, train like me, eat like this'.

"I don't know why he chose me, he must have seen something in me.

"By then I only played 40-odd first grade games and I was in and out of the team.

"That off-season we trained pretty hard and got to know each other.

Nuuausala spent a decade with the Roosters and admits it's been a difficult adjustment leaving the only club he has every played for.

"I went there when I was 18, I was a bit broken hearted and in pieces when I was a kid," Nuuausala said.

"They moulded me into a man and turned my life around and I owe everything for it.

"But now I'm at the Raiders and hopefully I can return their support back on the paddock."