White will be replaced by Michael Dowsett in a scrumhalf rotation a week after he missed an after-the-siren penalty attempt which would have lifted the Brumbies to a win against the Auckland Blues.

The Brumbies were tightlipped on Thursday about White's move to the bench as part of a massive back-line re-shuffle for the clash against the Melbourne Rebels, only saying new No. 9 Dowsett deserved his chance to start.

White didn't train on Thursday morning, adding a bit of mystery to the decision as the Brumbies manage his work load and coach Stephen Larkham also called in former Australian under-20s scrumhalf Joe Powell as a back up.

The selection move has opened the door for Dowsett to stake his claim for a more permanent role when White moves his career to France after the World Cup.

The Brumbies are going on a global search to find a suitable replacement for White, testing the recruitment waters with South African Fourie du Preez, New Zealand's Andy Ellis and France's Freddie Michalak.

But Dowsett wants to show Larkham he can fill White's boots as the 22-year-old aims to launch himself on to the radar to be the long-term successor.

"It's more just worrying about my development, I guess [Larkham] hasn't made that decision [about who will replace White next year] so I've got to keep working hard and make the decision for him," Dowsett said.

"I'd be lying if I said I didn't see myself in that No. 9 jersey going forward next year and that's my goal.

"But the focus is the Rebels this weekend, if I think too much further ahead than that then I wouldn't be doing the Rebels justice.

"I knew I'd get a chance to start somewhere along the line, so I'm just excited for an opportunity."

Injuries have forced the Brumbies into a massive shake up as they attempt to get their season back on track in Canberra.

White has had limited training duties this week with Powell stepping in to be ready for a late call up on to the bench if required.

Matt Toomua (ankle), Scott Sio (knee) and James Dargaville (foot) are all out of action for an extended period while Jesse Mogg, Fotu Auelua and Tevita Kuridrani have returned to training, but aren't ready for full contact.

The Brumbies' back line has been decimated by injuries, forcing Larkham's hand in picking a 6-2 forwards-backs split on the bench for the first time this year.

Christian Lealiifano will move to flyhalf, Nigel Ah Wong will start in the No. 12 jersey and former Australian sevens player Lausii Taliauli gets his chance on the wing.

Lock Rory Arnold returns from a back injury, Jean-Pierre Smith replaces Sio and Rodney Iona and Allan Alaalatoa join the bench.

Dowsett has warmed the bench behind White for the past 18 months, playing just 29 minutes this year and failing to get any game time in the past two matches.

"Dows performed exceptionally well in the pre-season and in the National Rugby Championship last year," Larkham said.

"He hasn't had enough game time this year and we thought it would work really well if Dows starting and Whitey coming off the bench."

Dowsett is excited about the prospect of more game time and working with White to become a better player.

The pair first crossed paths at schoolboy level, when Dowsett was a touch judge for a game White was playing in and now they have teamed up to chase a victory against the Rebels.

"Anything coming from Whitey will just be encouragement, he's focused on the goal of winning, not anything personal," Dowsett said.

"Whitey was the first bloke to come and shake my hand and said, 'have fun with it mate'. He asked if I needed anything along the way, his goal is to win as much as it is to start."

SUPER RUGBY ROUND NINE

Saturday: ACT Brumbies v Melbourne Rebels at Canberra Stadium, 7.40pm. TV time: Live on Fox Sports. Tickets available from Ticketek.

Brumbies team: 15. Robbie Coleman, 14. Lausii Taliauli, 13. Henry Speight, 12. Nigel Ah Wong, 11. Joseph Tomane, 10. Christian Lealiifano, 9. Michael Dowsett, 8. Jarrad Butler, 7. David Pocock, 6. Scott Fardy, 5. Sam Carter, 4. Rory Arnold, 3. Ben Alexander, 2. Stephen Moore, 1. Jean-Pierre Smith. Reserves: 16. Josh Mann-Rea, 17. Allan Alaalatoa, 18. Ruan Smith, 19. Blake Enever, 20. Jordan Smiler, 21. Ita Vaea, 22. Nic White, 23. Rodney Iona.