The ARL Commission approved the introduction of an 18^th man from round five onwards on Tuesday, but only under very strict conditions.

Three players must fail their head injury assessments before the extra substitute can be activated - and that player must be an emerging player, with the definition of what that is yet to be revealed.

It meant the Raiders wouldn't have been able to use the rule despite having only one fit player on the bench for 67 minutes in their gutsy loss to the New Zealand Warriors on Saturday.

Only Ryan James and Sebastian Kris were ruled out due to concussion with Joe Tapine coming off due to an ankle injury and Curtis Scott forced to play almost the entire game with broken ribs.

Cronulla would have been able to in their loss to Parramatta, where they lost three players to head knocks in the first half and spent the second 40 minutes with no fit players on the bench.

But Furner said that would be a rarity.

"I haven't really digested it, but I'm not sure where the number three came up," he said.

"I'm not sure who came up with that number or why. I'm not sure the reasons why that was the magic number because it seems highly unlikely that that will happen. Very, very, very rarely."

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Before the ARLC met, Raiders co-captain Josh Hodgson backed the introduction of an 18^th man saying you wanted to have the best players on the field.

He felt the speed of the game could be the cause of the spate of injuries early in the season - given last year the high numbers were put down to either the speed or the same-day travel.

There hasn't been any same-day travel so far this season.

"You want to be fast and entertaining, but there's no point if you haven't got the best players playing," Hodgson said.

"It's tricky. It could just be a freak couple of weeks, if not we should certainly have a look at tweaking a few things."

At this stage the Raiders clash against the Gold Coast Titans will go ahead as planned, despite there being a COVID-19 case on the Gold Coast.

The Green Machine were due to fly up on Thursday to do their captain's run.

The Queensland government said there was one coronavirus case on the Gold Coast, but they haven't extended the lockdown to include the area.

Hodgson said they would be ready for any eventuality - which could include a chartered flight and travelling up and back on game day.

"After last year I don't think anything will really faze the lads," he said.

"We had to travel up and back to Queensland multiple times last year - even for the prelim up there against Melbourne - so no matter what happens we'll be right mate.

"If last year taught us anything it's to be a bit mentally tougher in terms of preparation on game day. We'll be fine."

NRL ROUND FOUR

Saturday: Canberra Raiders v Gold Coast Titans at the Gold Coast, 7.35pm.

Raiders squad: 1. Charnze Nicoll-Klokstad, 2. Bailey Simonsson, 3. Jarrod Croker (c), 4. Sebastian Kris, 5. Jordan Rapana, 6. Jack Wighton, 7. George Williams, 8. Josh Papalii, 9. Josh Hodgson (c), 10. Dunamis Lui, 11. Hudson Young, 12. Elliott Whitehead, 13. Ryan Sutton. Interchange: 14. Tom Starling, 15. Siliva Havili, 16. Sia Soliola, 17. Ryan James. Reserves: 18. Sam Williams, 19. Semi Valemei, 20. Caleb Aekins, 21. Emre Guler.

Titans squad: 1. Alexander Brimson, 2. Anthony Don, 3. Phillip Sami, 4. Patrick Herbert, 5. Corey Thompson, 6. Tanah Boyd, 7. Jamal Fogarty, 8. Jarrod Wallace, 9. Mitch Rein, 10. Tino Fa'asuamaleaui, 11. Kevin Proctor, 12. David Fifita, 13. Tyrone Peachey. Interchange: 14. Moeaki Fotuaika, 15. Sam Lisone, 16. Jaimin Jolliffe, 17. Erin Clark. Reserves: 18. Beau Fermor, 19. Herman Ese'ese, 20. Sam McIntyre, 21. Brian Kelly.