But Fox League expert commentator Michael Ennis is confident the Green Machine can cover his absence - both following shoulder surgery and also if he was to leave at the end of the season.

Bateman went under the knife on Thursday morning for a second bout of surgery on his troublesome shoulder.

It's unclear when he'll return, but the England international responded to The Canberra Times' story on Twitter on Wednesday night to vow he hadn't played his last game for the Raiders.

On top of the injury, there's uncertainty around Bateman's contract.

While the 26-year-old is signed with Canberra for 2021, he's been given permission to explore his options, with a return to Wigan in the English Super League on a five-year, $3.5 million contract one option.

Ennis didn't know the ins and outs of Bateman's contract saga, but said given how important his daughter Millie was to him no one would begrudge the star second-rower returning to England to be closer to her.

Bateman's also been linked to Canterbury, the Gold Coast and St George Illawarra. His manager Isaac Moses didn't return The Canberra Times' calls.

"It would be a big loss to not have him a part of the competition or the Raiders," Ennis said.

"He seems to like Canberra to me. He brought so much there.

"[Raiders coach Ricky Stuart] and [chief executive Don Furner] and all the people at the club in all my short time there have been really strong - and we see that in the style of footy they play - they just don't rely on one individual.

"It's a great team they've got at the moment and they get contribution from everyone.

"John's contribution last year was huge, but we've seen this year even whan John hasn't been able to play with injury other guys have really stepped up and made sure their contribution has been excellent."

MORE RAIDERS NEWS

Bateman's yet to play a game for the Green Machine this year after undergoing his first round of shoulder surgery in February.

Four months later and he's needed more surgery.

It's come on the back of a very public push by his manager for a contract upgrade the Raiders don't currently have room for in their 2021 salary cap.

The Raiders have allowed him to test his value on the open market.

Bateman's previous manager was responsible for his current contract, which likely means Moses won't get paid until his client signs a new one.

It's coincided with the Raiders' beating the Melbourne Storm in Melbourne for the third time inside a year and becoming NRL premiership favourites.

Raiders co-captain Jarrod Croker said all the drama surrounding Bateman wasn't overshadowing their efforts on the field and it wasn't a distraction.

If the Raiders beat the Newcastle Knights at Campbelltown on Sunday it will be just the fourth time the club has started the season with four straight victories.

"It's not something that's overshadowed us. It's not something that's got to us," Croker said on Thursday.

"The whole 'Batty' situation hasn't really affected anyone. All the outside talk of who's favourites and beating Melbourne hasn't really affected anyone.

"We've got such a long season, we know we've got a lot of travel ahead of us ... we're not thinking too far ahead because it will just drain you mentally."

Croker was unsure how long Bateman would be out, having only heard he would need surgery on Wednesday.

All he'd heard was what the England forward had posted on Twitter in response to the story asking whether he'd played his last game in lime green.

"No iv (sic) not mate," he tweeted on Wednesday.

Croker hoped Bateman wouldn't be out for too long, but he backed the squad to continue to cover his absence.

"Obviously disappointing news to hear [Wednesday] arvo, unfortunately that's the game we play, but every side has injuries," he said.

"Obviously Johnny's a big one for us. We've had Joe Tapine play there the last couple of weeks and he's been doing a great job there so I'm sure 'Taps' will be able to fill that hole for Johnny in the meantime."

NRL ROUND FOUR

Sunday: Canberra Raiders v Newcastle Knights at Campbelltown Stadium, 4.05pm.

Raiders team: 1. Charnze Nicoll-Klokstad, 2. Bailey Simonsson, 3. Jarrod Croker, 4. Curtis Scott, 5. Nick Cotric, 6. Jack Wighton, 7. George Williams, 8. Josh Papalii, 9. Josh Hodgson, 10. Dunamis Lui, 11. Joe Tapine, 12. Elliott Whitehead, 13. Corey Horsburgh. Interchange from: 14. Siliva Havili, 15. Emre Guler, 16. Sia Soliola, 17. Jordan Rapana, 18. Tom Starling, 19. Matt Frawley, 20. Kai O'Donnell, 21. Michael Oldfield.

Knights team: 1. Kalyn Ponga, 2. Edrick Lee, 3. Enari Tuala, 4. Bradman Best, 5. Hymel Hunt, 6. Kurt Mann, 7. Mitchell Pearce, 8. David Klemmer, 9. Andrew McCullough, 10. Daniel Saifiti, 11. Aidan Guerra, 12. Sione Mata'utia, 13. Herman Ese'ese. Interchange from: 14. Tex Hoy, 15. Jacob Saifiti, 16. Tim Glasby, 17. Brodie James, 18. Gehamat Shibasaki, 19. Chris Randall, 20. Mason Lino, 21. Pasami Saulo.