The Brumbies have rolled the dice with four changes to their starting XV and four new players on the bench for their clash against the Queensland Reds at Canberra Stadium.

It was a complex thought process for McKellar, who was weighing up the need to refresh some players, find game time for others and maintain winning momentum before the play-offs next week.

Henry Speight (foot) failed to recover from injury, while Tom Cusack, Toni Pulu and Darcy Swain have been rotated out of the game-day squad.

That opens the door for Jahrome Brown to start at No. 7, Tom Wright to get his chance on the wing and Murray Douglas to take up a bench spot.

Lachlan McCaffrey starts his first game since April with Pete Samu shifting to the bench and Scott Sio will wear the No. 1 jersey in his 100^th game as part of a regular prop rotation with James Slipper. Ryan Lonergan, Len Ikitau and Jordan Jackson-Hope have been added to the bench.

"The [players] were OK. They're always a bit nervous because they're giving a chance to someone else [if they're not playing]," McKellar said.

"But someone like Cusack has a lot of runs on the board with recent performances, so you try to put their mind at ease and acknowledge the contribution, and understand they'll be involved next week.

BRUMBIES NEWS

"Toni has played more consecutive games than he has in his career. So this gives Wrighty another opportunity ... there's certainly no disrespect. It's taking an opportunity to freshen a few people up and I think we're replacing them with outstanding footballers."

The Brumbies have secured their place at the top of the Australian conference and will most likely finish third on the overall Super Rugby ladder at the end of the regular season.

Sealing their finals fate has given McKellar an opportunity to think ahead for the first week of the play-offs. But the Reds will be determined to cause an upset to finish their season on a high.

The Brumbies are chasing their sixth consecutive win, which would equal the record for the longest winning streak in the club's history. They are also aiming for their seventh win in a row in Canberra.

Maintaining that form is crucial to the Brumbies' hopes of advancing through the finals and being a genuine contender to win their first title in 15 years.

"I hope it shows [the confidence in our depth], we've been really pleased with how our younger players coming along and it's nice to give them that opportunity," McKellar said.

"We've got a home quarter final so we want to get our performance right [this week] in front of our home crowd so they all come back and bring a few friends for the quarter final.

"It's really important [to keep winning], we don't want to put a pin in the balloon at this time of the year. We've just got to keep doing what we've been doing well."

The Reds haven't won in Canberra since 2014.

SUPER RUGBY ROUND 18

Saturday: ACT Brumbies v Queensland Reds at Canberra Stadium, 7.45pm. Tickets available from Ticketek.

Brumbies: 1. Scott Sio, 2. Folau Faingaa, 3. Allan Alaalatoa, 4. Rory Arnold, 5. Sam Carter, 6. Rob Valetini, 7. Jahrome Brown, 8. Lachlan McCaffrey, 9. Joe Powell, 10. Christian Lealiifano, 11. Tom Wright, 12. Irae Simone, 13. Tevita Kuridrani, 14. Andy Muirhead, 15. Tom Banks. Reserves: 16. Connal McInerney, 17. James Slipper, 18. Les Leuluaialii-Makin, 19. Murray Douglas, 20. Pete Samu, 21. Ryan Lonergan, 22. Len Ikitau, 23. Jordan Jackson-Hope.

Reds: 1. JP Smith, 2. Alex Mafi, 3. Taniela Tupou, 4. Izack Rodda, 5. Harry Hockings, 6. Lukhan Salakaia-Loto, 7. Liam Wright, 8. Angus Scott-Young, 9. Scott Malolua, 10. Matt McGahan, 11. Filipo Daugunu, 12. Samu Kerevi, 13. Chris Feauai-Sautia, 14. Jock Campbell, 15. Bryce Hegarty. Reserves: 16. Brandon Paenga-Amosa, 17. Ruan Smith, 18. Gav Luka, 19. Caleb Timu, 20. Scott Higginbotham, 21. Moses Sorovi, 22. Duncan Paia'aua, 23. Sefa Naivalu.