The pair's absence makes way for Brackin Karauria-Henry to receive his first starting cap after making his Super 14 debut against the Waratahs last weekend.
The 21-year-old Australian Sevens representative will play off the left wing allowing Adam Ashley-Cooper to return to his preferred position at fullback. Andrew and Tyrone Smith maintain their midfield partnership with Josh Valentine and Matt Giteau forming the halves.
The Brumbies forward pack remains unchanged from last week, however, Jerry Yanuyanutawa returns to the 22-man squad for the second time this season off the bench.
The reserve backs have also received a shake up with Queanbeyan inside back Robbie Coleman in line to become the eighth Brumbies player to make his Super 14 debut this season, with all eight involved on Saturday night.
Coleman's Australian Sevens teammate, Ed Stubbs, returns to the bench after making his provincial debut for the ACT side against the Cheetahs three weeks ago.
Brumbies Head Coach Andy Friend says his side is ready for a big match against the Queenslanders.
"We said from the outset that one of the strengths of this side was its depth and that's certainly been tested this season," he said. "The positive thing is that everyone who's come in to fill a vacancy has risen to the challenge and has shown that they are capable of playing Super 14 rugby.
"This is a great opportunity for Brackin and Robbie to get their first starting cap and debut respectively. They've both played a fair amount of senior rugby at club level, with the Runners and the Australian Sevens side and they're very composed individuals who will make the most of this opportunity."
The Brumbies' match against the Reds will be marked with the ACT side supporting OzHarvest Canberra logos on the front of their jerseys while fans will also be invited onto the field after the match.
Brumbies Team
1. Ben Alexander 2. Stephen Moore 3. Salesi Ma'afu 4. Mitchell Chapman 5. Mark Chisholm 6. Rocky Elsom 7. Colby Faingaa 8. Stephen Hoiles (c) 9. Josh Valentine 10. Matt Giteau 11. Brackin Karauria-Henry 12. Tyrone Smith 13. Andrew Smith 14. Pat McCabe 15. Adam Ashley-Cooper
Reserves:16. Huia Edmonds 17. Jerry Yanuyanutawa,18. Ben Hand 19. Michael Hooper 20. Patrick Phibbs 21. Robbie Coleman 22. Ed Stubbs
.jpg)
