Valetini is edging closer to a Super Rugby debut after being picked in the ACT Brumbies' starting side for the last pre-season trial on the Sunshine Coast.

Coach Dan McKellar is rolling out a full-strength side - barring David Pocock - and Valetini has emerged as a genuine round-one bolter.

The 19-year-old rookie back-rower is already 113 kilograms and 193 centimetres and is rated as one of the hardest hitters at Brumbies HQ.

He impressed so much in his first year that the Brumbies offered him a two-year contract extension despite not playing a game.

"I feel a bit more confident this year I think. Last year was just about getting used to it, hopefully I can put my hand up to get a starting spot or even just that first game," Valetini said.

"I think I've got the confidence to back myself this year. Knowing I had two years to learn really helped me to pick things up last year and learn the professional system.

"A Super Rugby debut is my goal this year. That's what I'm aiming for and then just game time."

Valetini will form part of a new-look Brumbies back-row as McKellar tests new combinations before the Super Rugby season starts on February 24.

Valetini will fill Scott Fardy's role at blindside flanker, Western Force recruit Isi Naisarani will slot into the No. 8 position and Lachlan McCaffrey has a chance to stake his claim to do the openside flanker job.

McKellar says spots are still up for grabs for the opening round of the season.

Christian Lealiifano makes his comeback at flyhalf, Tom Banks appears to be the front-runner for the fullback spot and Scott Sio and Tevita Kuridrani return in their familiar roles.

Veteran hooker Josh Mann-Rea is also making his comeback after a seven-month layoff, and he'll unleash his game-free frustration on the Chiefs.

Mann-Rea hasn't played a game since July 22 when the Brumbies were knocked out of the Super Rugby finals race, juggling training and farm work in the past seven months.

"I can't wait. I was spewing that I didn't get to go out there against the Rebels two weeks ago, so I can't wait for the game," Mann-Rea said.

"It's one thing running around at training, but it's another battle in a game. There's nothing like when you're out on the field and in battle.

"I'd get flogged at training and then work on the farm. I'm very lucky I can go out to Jugiong and work at the property, get my head away and have a good balance.

"But you just miss it and miss ripping in. It was hard to watch the guys play [for the Canberra Vikings], finally the time has arrived and this is going to be a massive test for us."

The Brumbies haven't beaten a New Zealand team since the opening round of the Super Rugby season in 2016.

"We've got to step up against the Chiefs, it's going to be bloody hard," Mann-Rea said.

"It doesn't matter who you're playing, you want to play well and start to build momentum. It's always a bonus to get a win at the start of the year, it builds confidence."

Mann-Rea, 36, has signed a contract extension to continue his career until at least the end of the 2020 season.

He will compete with Folau Faingaa and Robbie Abel for a starting spot, and has overcome a niggling hamstring strain to be fit for the start of the season.

SUPER RUGBY TRIAL

Wednesday: ACT Brumbies v Waikato Chiefs at Sunshine Coast Stadium, 8pm. Live stream on brumbies.com.au.

Brumbies team: 15. Tom Banks, 14. Henry Speight, 13. Tevita Kuridrani, 12. Kyle Godwin, 11. Chance Peni, 10. Christian Lealiifano, 9. Joe Powell, 8. Isi Naisarani, 7. Lachlan McCaffrey, 6. Rob Valetini, 5. Sam Carter, 4. Rory Arnold, 3. Allan Alaalatoa, 2. Josh Mann-Rea, 1. Scott Sio. Reserves: Robbie Abel, Ben Alexander, Leslie Leuluaialii-Makin, Blake Blake Enever, Richie Arnold, Tom Cusack, Lolo Fakaosilea, Matt Lucas, Wharenui Hawera, Lausii Taliauli, Andrew Smith, James Dargaville, Andrew Muirhead.