Much of the pre-game hype has centred around the clash of the back rows, with the Brumbies losing David Pocock (suspension) and Ita Vaea (retired), while former Test coach Bob Dwyer launched a grenade into the NSW camp on Friday by claiming Michael Hooper was the fifth best Australian No.7 this season.

But Hoiles, who won a Super Rugby title with NSW in 2013, said Beale looms as the linchpin in his return from injury and with Israel Folau shifting to outside centre.

The Waratahs have lost three of their five games this season and sit well down the overall standings on 12 points. Another loss would put a major dent in their finals aspirations.

"I would hope with the position the Waratahs are in that it's all or nothing this weekend," Hoiles said at the Brumbies' State of the Union lunch on Friday.

"Kurtley is the big one for me and the big in. Losing two centres is pretty significant to a side and that's what happened last time for the Tahs.

"I think he's a huge addition, but I've got no idea how it's going to go. The Brumbies will be hurting, but the Tahs will be really hurting."

The Brumbies are still stinging after suffering a last-start loss to the Waikato Chiefs two weeks ago. The 48-23 scoreline was the biggest home defeat in Brumbies history.

But coach Stephen Larkham is backing his combinations, opting to make just two changes to the starting XV with Jarrad Butler and Jordan Smiler to replace Pocock and Vaea, respectively.

In contrast, Waratahs coach Daryl Gibson has made five changes to his side, including dropping club captain Dave Dennis to the bench and injecting giant Will Skelton.

The Brumbies started the season with three consecutive wins, but have lost two of their past three matches.

Brumbies scrumhalf Tomas Cubelli said: "We know it's an important game against another team in our conference ... we need to keep improving our game if we want to reach the finals. We needed some energy for these next five games."

SUPER RUGBY ROUND EIGHT

Saturday: NSW Waratahs v ACT Brumbies at Sydney Football Stadium, 7.45pm. Tickets available from Ticketek TV time: Live on Fox Sports 2

Brumbies: 15. Aidan Toua, 14. Robbie Coleman, 13. Tevita Kuridrani, 12. Matt Toomua, 11. Joseph Tomane, 10. Christian Lealiifano, 9. Tomas Cubelli, 8. Jordan Smiler, 7. Jarrad Butler, 6. Scott Fardy, 5. Sam Carter, 4. Rory Arnold, 3. Ben Alexander, 2. Stephen Moore, 1. Scott Sio. Reserves: 16: Josh Mann-Rea, 17. Allan Alaalatoa, 18. Les Leuluaialii-Makin, 19. Tom Staniforth, 20. Michael Wells, 21. Joe Powell, 22. James Dargaville, 23. Nigel Ah Wong.

Waratahs: 15. Andrew Kellaway, 14. Reece Robinson, 13. Israel Folau, 12. Kurtley Beale, 11. Matt Carraro, 10. Bernard Foley, 9. Nick Phipps, 8. Jed Holloway, 7. Michael Hooper, 6. Jack Dempsey, 5. Will Skelton, 4. Dean Mumm, 3. Tom Robertson, 2. Hugh Roach, 1. Benn Robinson. Reserves: 16. James Hilterbrand, 17. Paddy Ryan, 18. Angus Taavao, 19. Sam Lousi, 20. Wycliff Palu, 21. David Dennis, 22. Matt Lucas, 23. David Horwitz.