Butler will make his comeback from injury when he steps into David Pocock's No.7 jersey for a duel against Michael Hooper and the NSW Waratahs on Saturday night.

The Brumbies have been working with Butler and his management for the past two months to finalise a long-term deal to secure his future.

It is believed both parties are close to reaching an agreement in what looms as a massive boost on the back of Ita Vaea's premature retirement this week.

The Brumbies will have to find a way to cover the absence of Pocock and Vaea for the 2017 Super Rugby season.

Pocock is taking a sabbatical before returning for the 2018 campaign while Vaea retired due to a heart condition.

Butler and Jordan Smiler have been thrust into the Brumbies' back row to replace the duo this week, teaming up with Scott Fardy for a brutal battle against the Waratahs.

"Irrespective of whether Ita and Poey were going to be here or not, all of those guys [who are off contract] are important to us and we've been trying to complete negotiations for a while," Butler said.

"It's just the way they go, they always take a bit longer. But the culture and the environment here is very strong.

"JB's got some experience in this team and we're trying to keep all of these guys together for as long as possible. Jarrad's filled in at No.7 for us in the past and done a fantastic job.

"We don't need to change anything in terms of the way we're playing ... that's the beauty of Jarrad, he's a class player, he's been here for a number of years and he's invaluable to the team whether he's starting or coming off the bench."

The Brumbies have made few changes to the team that lost to the Waikato Chiefs two weeks ago, with Butler and Smiler the only new faces in the starting side.

"Going into the Chiefs game that was our best combination, nothing's changed. Our policy is to settle on our best team and it doesn't change just because a result goes against us," Larkham said.

Butler has to get through a training session on Friday to prove he has recovered from a knee injury, with former Australian sevens player Michael Wells added to the bench.

The Waratahs have made sweeping changes, including benching club captain Dave Dennis, for the clash at Allianz Stadium.

The Waratahs have opted for a six-two split of forwards and backs on the bench, with Dennis and Palu to be injected in the second half.

Coach Daryl Gibson has picked Israel Folau at outside centre for the first time in a centre partnership with Kurtley Beale that will have the Brumbies midfield on edge.

Butler hasn't played since the Brumbies beat the Western Force last month, but he has proven his worth having stepped in for Pocock in the 2013 season to win the ACT club's player of the year award.

"Jarrad understands rugby, he's extremely skilful. If Jarrad's not right to go, we'll have Michael [Wells] ready to step in there," Larkham said.

"Every game in Super Rugby is basically a final, that's the way we approach it. This game is no more important or less important than other games.

"There's always a fierce rivalry between us and the Waratahs. You try to win every week whether you're playing an Australian team or South Africa team. If we do our job each week, we'll be where we need to be at the end of the year."

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.