Alexander said there's "half a dozen" Raiders in the Blues mix and has encouraged them to use the Sydney Roosters clash at Canberra Stadium on Sunday as the perfect opportunity to stake their claim for the future.

NSW winger Blake Ferguson was the last member of the Green Machine to debut for the Blues - back in 2013.

And there's only been seven Raiders who've made their debut for the Blues in the last 20 years - Ferguson, Josh Dugan, Tom Learoyd-Lahrs, Terry Campese, Joel Monaghan, Ryan O'Hara and Ben Kennedy.

Blues coach Laurie Daley again overlooked his old club when he picked his squad for Wednesday's State of Origin opener against the dominant Queensland Maroons at Suncorp Stadium.

Croker's ultra-consistency has him knocking down the door to make his Origin debut after he was 19th man three years ago.

The Raiders captain's a point- and try-scoring machine, but Daley opted for fullback Hayne ahead of him in Croker's position at left centre on the back of his efforts in the 2014 Origin series - the last time NSW beat Queensland.

But Alexander said Croker couldn't "do any more" to state his case and predicted he would be in contention for Origin II if Hayne doesn't fire.

"He's doing what he needs to do, but they've got Jarryd Hayne at left centre. Whether you like it or not, Hayne's been good in Origin in the past," Alexander said.

"He's probably playing out of position, but if he doesn't handle it Jarrod's there.

"I don't think they'd have any hesitation picking Jarrod if things don't work with Jarryd Hayne, I'm sure they have confidence in him getting the job done."

Croker's Raiders teammates Shannon Boyd, Junior Paulo and Joey Leilua have also been spoken about as possible Blues players, but Queensland second-rower Josh Papalii was the only Green Machine player to get the Origin call-up.

Alexander, who played six Origins for NSW and six Tests for Australia, said the best way for them to respond was to show the selectors they were "next in line" with their performance against the Roosters.

While it's a Roosters side without five Origin stars, including co-captain Boyd Cordner and halfback Mitchell Pearce, Alexander said it was still a "quality side" that couldn't be taken lightly.

He said Raiders coach Ricky Stuart wouldn't have needed to tell his players they would still be dangerous.

"They're close, they've played rep footy and had a taste," Alexander said.

"If I wasn't picked and I was as close as those blokes are I'd want to make sure I had a big game to let those know that pick the sides that they either made a mistake or if there's an opportunity, injury, poor form that I'm the next in line.

"That's what I'd be thinking if I was any one of those blokes that are on the fringes, and there's half a dozen blokes in that position, just underneath the selection."

Alexander said focus was the key for the Raiders, who were coming off a "scratchy win" against the Parramatta Eels last weekend.

He said that would mean they'd produce less errors and control the ball, making them "almost impossible to beat".

The Fox Sports commentator said a second consecutive NRL finals campaign would also help bolster the representative chances of the Green Machine.

Even if an Origin berth didn't arrive, there were still World Cup spots on the line through performances from the rest of the season.

"It mightn't be Origin, but it might be Australia in the World Cup, so it always helps if your side plays deep into the finals series," Alexander said.

"Which the Raiders would be, off the back of what they did last year, they'd be expecting to do at least that this year."

NRL ROUND 12

Sunday: Canberra Raiders v Sydney Roosters at Canberra Stadium, 4pm. Tickets available from Ticketek. The jerseys will be auctioned at allbids.com.au.

Raiders squad: 1. Jack Wighton, 2. Nick Cotric, 3. Jarrod Croker (c), 4. Joey Leilua, 5. Jordan Rapana, 6. Blake Austin, 7. Aidan Sezer, 8. Junior Paulo, 9. Josh Hodgson, 10. Shannon Boyd, 11. Joe Tapine, 12. Elliott Whitehead, 13. Sia Soliola. Interchange: 14. Adam Clydsdale, 15. Luke Bateman, 16. Clay Priest, 17. Dunamis Lui. Reserves: 19. Scott Sorensen, 21. Lachlan Croker.

Roosters squad: 1. Michael Gordon, 2. Daniel Tupou, 3. Latrell Mitchell, 4. Mitchell Aubusson, 5. Joseph Manu, 6. Connor Watson, 7. Luke Keary, 8. Jared Waerea-Hargreaves, 9. Jake Friend (c), 10. Kane Evans, 11. Ryan Matterson, 12. Siosiua Taukeiaho, 13. Zane Tetevano. Interchange: 14. Isaac Liu, 15. Lindsay Collins, 16. Chris Smith, 17. Mitchell Cornish. Reserves: 18. Nat Butcher, 20. Eloni Vunakece.