Five games into his NRL return, Tuivasa-Sheck has slowly begun to recapture the form which earned him a move to rugby union and debut for the All Blacks.
There was a great deal of speculation that the one-time Golden Boot winner would reclaim the coveted No.1 jersey after returning to the Warriors.
But after Nicoll-Klokstad's gutsy effort in his comeback from injury against South Sydney last week, Tuivasa-Sheck says his days of carting the ball up from the back are long gone.
He (Nicoll-Klokstad) is not a good NRL player, he's a world-class player," said Tuivasa-Sheck, who has mainly featured at centre since returning to rugby league.
"He's shown that on the NRL stage and he's shown that on the international stage that he's a world-class one, and I back him 100 per cent.
"He's our fullback, our coach has said he's our fullback, he believes he's the best fullback, and I believe it too.
"I've been training in the centres, but if I need to play anywhere else, I'll do it."
Roger Tuivasa-Sheck (c) has been used in the centres by the Warriors. (Andrew Cornaga/AAP PHOTOS)
Tuivasa-Sheck's return to the NRL has also set tongues wagging about where his international loyalty sits.
The 30-year-old missed out on the 2022 Rugby League World Cup, where he was eligible to represent New Zealand and his ancestral homeland of Samoa, who reached the final.
Tuivasa-Sheck has been publicly pursued by new Samoa coach Ben Gardiner, but his close bond with new Kiwis coach Stacey Jones may ensure his allegiance remains with New Zealand.
Asked if he had chosen between the two countries, Tuivasa-Sheck said: "That's a really good question, and I don't have an answer for that.
"I was in All Blacks camp at the time when they were playing the finals, and all of us Samoan boys in the camp – led by Ardie Savea – we were just cheering them.
"We were proud to see this small island playing on the big stage against England, I was just so happy for those boys.
"I was happy for the small island of Samoa to play on the big stage."
