Brumbies winger Henry Speight will not play against the Reds, withdrawing with injury.
Speight failed a Friday morning fitness test on the eve of the match, with the Brumbies ruling the speedster out of the Australian derby.
The 30-year-old will be replaced by James Dargaville in the starting side, with the move a straight swap.
Speight was set to play his 100th match on Saturday, but that will have to wait another week at least as he looks for full fitness.
The Brumbies face a near must-win situation in the matchup, as they look to keep their Super Rugby finals hopes alive in 2018.
The Brumbies host the Reds on Saturday night at Canberra Stadium, kicking off at 7:45pm AEST, LIVE on FOX SPORTS and via RUGBY.com.au RADIO. Buy tickets here.
TEAM
IN: James Dargaville, Chance Peni, Les Makin, Sam Carter, James Verity-Amm
OUT: Henry Speight, Andy Muirhead, Mees Erasmus, Richie Arnold, Lausii Taliauli
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Brumbies to face the Reds
1. Scott Sio
2. Folau Fainga’a
3. Allan Alaalatoa
4. Rory Arnold
5. Blake Enever
6. Lachlan McCaffrey
7. David Pocock
8. Isi Naisarani
9. Matt Lucas
10. Wharenui Hawera
11. Chance Peni
12. Christian Lealiifano
13. Tevita Kuridrani
14. James Dargaville
15. Tom Banks
Reserves
16. Robbie Abel
17. Faalelei Sione
18. Leslie Leuluaialii-Makin
19. Sam Carter
20. Tom Cusack
21. Joe Powell
22. Kyle Godwin
23. James Verity-Amm