Banks will start in the No. 15 jersey for the Vikings' clash against the Western Force in Perth after Toni Pulu was ruled out with illness.

The fleet-footed fullback returned to Australia on Sunday after training with an extended Wallabies squad as injury cover.

It put the 25-year-old so close to his World Cup dream he could touch it, even having his photo taken in official playing kit before being forced to leave camp as per tournament regulations.

Getting a taste has ignited the desire to be in the main squad in four years and he will use the National Rugby Championship to stay in form should he be required as a late addition in Japan.

"It's been a rollercoaster," Banks said. "But that's footy and you've got to learn to deal with it.

"I'm excited to be playing some footy again and getting back into the rhythm of it.

"It hit home that I wasn't part of the main squad when I did get on that plane to come back to Australia.

"That was tough. But it's also quite motivating ... it really makes you realise what you want to do and I want to be there for the next one.

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"I know it's a long time away, but it instills that motivation. I'm obviously disappointed that I'm not in there, but you have to move forward and be ready for anything that happens."

The Wallabies will start their campaign with a clash against Fiji at almost exactly the same time Banks is playing for the Vikings in a crucial clash against the Force.

Banks is expected to play the rest of the NRC season and the Wallabies will be monitoring him closely as they sweat on Jordan Petaia recovering from a hamstring injury.

Christian Lealiifano is in contention to make his World Cup debut as the starting flyhalf and David Pocock could be thrust into the back row after playing just one game since March.

Banks has narrowed his focus to NRC form to avoid being caught in the World Cup hype and returning to the NRC is an opportunity to reset.

"The NRC is somewhere you can come back to and get that enjoyment," Banks said.

"It's fast-flowing footy that you miss from time to time, so that's something I'm really looking forward to.

"Don't get me wrong, it's disappointing not to be in Japan. But there are two ways you can go about it.

"If you're sulking about it, you're not going to get better and it will take a long time to get over it.

"I'm just trying to get back there and play good footy because you're not going to get much if you just sit there and sulk."

The Vikings have won two of their three games so far this season, but will perhaps face their biggest test against the Force side led by former Tuggeranong coach Tim Sampson.

The match will also give Brumbies players a chance to get a close look at two future teammates after Harry Lloyd and Issak Fines signed deals to return to Canberra for the 2020 Super Rugby season.

The Brumbies have just one roster spot left to fill for their squad next year, with coach Dan McKellar casting an eye over NRC talent before he completes his group of players. Banks will have a crucial role next season through a transitional period after the departure of Lealiifano, Pocock, Sam Carter and Rory Arnold.

NRC ROUND FOUR

Saturday: Western Force v Canberra Vikings at Perth, 5pm.

Vikings: 1. Fred Kaihea, 2. Lachlan Lonergan, 3. Nic Dobson, 4. Darcy Swain, 5. Blake Enever, 6. Pete Samu, 7. Luke Gersekowski, 8. Rob Valetini, 9. Joe Powell, 10. Noah Lolesio, 11. Mack Hansen, 12. Irae Simone, 13. Len Ikitau, 14. Andy Muirhead, 15. Tom Banks. Reserves: 16. TP Luteru, 17. Bo Abra, 18. Angus Wagner, 19. Nick Frost, 20 Will Miller, 21. Ryan Lonergan, 22. Bayley Kuenzle, 23. George Morseu.