But Canberra Raiders coach Ricky Stuart is confident young outside back Harley Smith-Shields can get the job done in the biggest game of the Green Machine's season - otherwise he wouldn't pick him to take on the towering Tupou.

It will just be Smith-Shields' ninth NRL game as the Raiders face a must-win clash against the Roosters at Mackay on Thursday night - needing to win to have a chance of making the top eight.

Bailey Simonsson's groin injury, set to sideline him for 1-2 weeks, meant Smith-Shields kept his spot in the 17.

Rapana will play on the left edge following the return of Charnze Nicoll-Klokstad (neck) to fullback.

Like Rapana, 196-centimetre Tupou's his team's leading try scorer - with 14 - while he also leads them for line breaks (17).

Also like Rapana, he rolls up his sleeves to do the hard work coming out of yardage and leads the Chooks for post-contact metres (1580), run metres (4113) and kick return metres (826) as well.

Stuart has told Smith-Shields he backed him to get the job done against one of the Roosters' most-important players.

"They kick the ball to him a lot and I can understand that strategy - he's very good in the air so we're expecting him to be bombing our right side," he said.

"I've got young Harley Smith-Shields, who I only just said to him, if I wasn't confident in him doing a job I'd swap sides with him with Jordan.

"But I think it's going to be a great experience for the young bloke to have a crack at this type of highly intense, important fixture.

"Harley's been really good. He's a centre playing on the wing at the moment and been very good for us.

"He'll get his opportunity [Thursday] night to mark a very experienced first grader."

MORE RAIDERS NEWS

The Canberra Times revealed Raiders co-captain Elliott Whitehead came to him requesting Sia Soliola play against the Roosters after the death of the big-hearted prop's mother.

Soliola could only join the memorial service via Zoom, having missed the past two games.

The 35-year-old's off contract at the end of the season, but Stuart said he hadn't talked to Soliola about next year.

Soliola's played 228 NRL games, for both the Raiders and Roosters, as well as 117 Super League games for St Helens.

He's played a big role in building Canberra's culture after Stuart brought him back to the NRL after five seasons in England.

"He's had a very, very distinguished career, but I'm yet to sit down with Sia," Stuart said.

"It's a really important part of the season and those discussions will be had at a later date.

"It's important that everyone fulfills their role and when you're a coach and you've got a guy like Sia you know exactly what you're going to get defensively [and] in attack. You trust the guy.

"I've known him for a long time and I know about his off-field commitments to the community and the Canberra Raiders - it's very similar on the field.

"The boys all look up to Sia - they call him uncle - and it's the type of respect he's earned."

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.