Former Wallabies captain David Pocock is breathing down Butler's neck for selection, while incumbent Test skipper Michael Hooper is on the other side of the fence ready to do battle in a blockbuster Australian derby against the NSW Waratahs.

But Butler is unfazed by the challenge to keep his spot in the Brumbies starting team and is refusing to look beyond his mission against former Australian junior teammate Hooper.

The 23-year-old has played so well this season that coach Stephen Larkham has given him a chance to keep the No. 7 jersey, while Pocock returns from injury on the bench.

His form has also rocketed him into Wallabies calculations, with Waratahs and Test coach Michael Cheika nominating Butler as a shock candidate for the Australian back row.

"It's confidence boosting to have the support [of Larkham] and Poey as well ... all I can do is work as hard as I can for the time that I'm out there," Butler said. "It's good pressure, you want to play well because you want to stay out on the field.

"If you've got no one pushing you, you won't be working hard. So I think it's a positive thing to have guys like Poey, who's always helping, and then a guy like Hooper on the other team."

Pocock has played just six games since the start of the 2013 season after having two knee reconstructions and injuring his ankle in the opening round this year.

His absence has given Butler a chance to establish himself in Canberra, and the humble back-rower won the club's top prize as the player of the year last season to join an honour roll that includes George Smith, Stirling Mortlock and Matt Giteau.

Butler has played every game of the past two seasons and his ability to play any position in the back row makes him a valuable asset to the Brumbies' title ambitions.

Cheika has recognised Butler's work rate - he has made the most tackles of any Australian player this season - and hasn't ruled out drafting Butler into the Test squad.

"It was really positive [to hear Cheika's comments], I was happy about that," Butler said.

"But it doesn't change anything this week ... this is the biggest game we've had so far, so all we are concerned about is trying to beat the Waratahs and putting ourselves in a good place coming into the middle [of the season]."

Butler admits he doesn't know where he will be able to lock down a long-term position in the Brumbies forward pack.

Pocock is one of the world's best players when fully fit, while No. 8 Ita Vaea has made a successful comeback from life-threatening blood clots.

"I definitely don't offer what Poey offers. He's one of the best pilferers in the game," the Wellington-born flanker said.

"And Hooper is very dynamic with ball carries. But I'm not here to compare myself, I'm just going to work hard. I don't know where I can play ... I think it's a week-to-week thing.

"Poey is the best in the world, Ita has been playing great, it just comes down to the week and hopefully you're in the mix. You want to be part of the starting XV, you want to be on the field. It's not fun being on the bench, but what can you do? Just keep playing well."

SUPER RUGBY ROUND SIX

Sunday: NSW Waratahs v ACT Brumbies at Allianz Stadium, 4.05pm. TV time: Live on Fox Sports 2.

Brumbies team: 15. Robbie Coleman, 14. Henry Speight, 13. Tevita Kuridrani, 12. Christian Lealiifano, 11. Joseph Tomane, 10. Matt Toomua, 9. Nic White, 8. Ita Vaea, 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. Ruan Smith, 18. Jean-Pierre Smith, 19. David Pocock, 20. Jordan Smiler, 21. Michael Dowsett, 22. James Dargaville, 23. Lausii Taliauli.

Waratahs team: 15. Israel Folau, 14. Taqele Naiyaravoro 13. Matt Carraro, 12. Kurtley Beale, 11. Rob Horne, 10. Bernard Foley, 9. Nick Phipps, 8. Wycliff Palu, 7. Michael Hooper, 6. Jacques Potgieter, 5. Dave Dennis, 4. Will Skelton, 3. Sekope Kepu, 2. Tolu Latu, 1. Benn Robinson. Reserves: 16. Hugh Roach, 17. Jeremy Tilse, 18. Paddy Ryan, 19. Sam Lousi, 20. Mitchell Chapman, 21. Stephen Hoiles, 22. Brendan McKibbin, 23. Jono Lance, 24. Peter Betham.