It's why the New Zealand international's return is so massive - especially before the Raiders' biggest game of the NRL season.

They need to beat the Sydney Roosters at Mackay on Thursday night to have a chance of making the NRL top eight, while also relying on the Melbourne Storm beating Cronulla the following night.

Although they could also sneak in if the Sharks win, provided the Raiders win by 50 points more than Cronulla do.

And an in-form Nicoll-Klokstad boosts the Green Machine's chances of knocking off the Roosters, even with the Bondi princes being bolstered by the return of Jared Waerea-Hargreaves, Angus Crichton and Josh Morris.

Nicoll-Klokstad will wear the No.1 jersey for the first time in almost five months, since undergoing what was believed to be season-ending neck surgery.

He suffered the injury against Penrith in round five, but has played Canberra's past two games coming off the bench - starring in their win over the New Zealand Warriors on Friday.

That shifts Jordan Rapana back to the wing - after the New Zealand international put in a brilliant shift at fullback that's culminated in him re-signing with the Green Machine for another two years.

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It covers the loss of Bailey Simonsson (groin), who was expected to miss 1-2 weeks with the injury he suffered in the first half of the Warriors win.

Raiders coach Ricky Stuart said it was nice to have that depth in the outside backs to help cover Simonsson.

The crucial clash against the Chooks will also see the return of Sia Soliola for his first game since the death of his mother 11 days ago.

Soliola will start at lock, with Ryan Sutton shifting to the bench.

The Canberra Times revealed in June the Raiders win 65.4 per cent of games with Nicoll-Klokstad at fullback, which drops to 40 per cent in his absence.

When he's the custodian they average 21.3 points per game, while only conceding 16.

That shifts to only scoring 19.3 when he's not there, while letting in 24.4.

It's more than a 10-point swing - or almost two converted tries - every time the Green Machine runs out.

"Statistically we missed Charnze. You've only got to look at the stats," Stuart said.

"It comes down to his professional approach. He's very committed to his training and rehabilitation and that's been very evident recently."

AT A GLANCE

Thursday: Canberra Raiders v Sydney Roosters at Mackay, 7.50pm.

Raiders squad: 1. Charnze Nicoll-Klokstad, 2. Harley Smith-Shields, 3. Sebastian Kris, 4. Matt Timoko, 5. Jordan Rapana, 6. Jack Wighton, 7. Matt Frawley, 8. Josh Papalii, 9. Josh Hodgson, 10. Joe Tapine, 11. Hudson Young, 12. Elliott Whitehead (c), 13. Sia Soliola. Interchange: 14. Emre Guler, 15. Ryan Sutton, 16. Corey Horsburgh, 17. Siliva Havili. Reserves: 18. Sam Williams, 19. Semi Valemei, 20. Elijah Anderson, 21. Trey Mooney.

Roosters squad: 1. James Tedesco, 2. Daniel Tupou, 3. Josh Morris, 4. Adam Keighran, 5. Matt Ikuvalu, 6. Drew Hutchison, 7. Lachlan Lam, 8. Jared Waerea-Hargreaves, 9. Sam Verrills, 10. Siosiua Taukeiaho, 11. Angus Crichton, 12. Sitili Tupouniua, 13. Isaac Liu. Interchange: 14. Sam Walker, 15. Egan Butcher, 16. Ben Marschke, 17. Tukupa Hau Tapuha. Reserves: 18. Moala Graham-Taufa, 19. Brad Abbey, 20. Naufahu Whyte, 21. Daniel Suluka-Fifita.