Palu will complete his shock comeback to Australian rugby on Friday night when he joins a beefed-up Waratahs bench for a crucial Super Rugby derby.

The 57-Test Wallaby was set to walk away from Test rugby and the Waratahs after the World Cup last year. In his absence the Wallabies opted for a super flanker combination of David Pocock and Michael Hooper at the back of the scrum for the World Cup.

But Australian rugby needs a big ball-carrying back-rower who can damage the opposition defensive line, and Brumbies No.8 Ita Vaea fits the requirements.

An injury twist delayed his move to Japan and opened the door for him to train in Sydney and sign with the Waratahs on a bargain extended player squad contract worth just $50,000.

Waratahs coach Daryl Gibson declared Palu was back to his powerful best for the match.

However, Palu is aware he's going into battle against a younger version of himself – recharged Brumbies wrecking ball Vaea.

Palu has hinted at his desire to wear Wallabies gold again, but Vaea is banging down the door after recovering from life-threatening blood clots.

"Ita just has to concentrate on consistently playing well, I've watched him run around and I've got a lot of respect for him," Palu said.

"He was playing really well before he got the blood clots and now he's back to that same form. To come back from something like that, it's massive.

"I think he's a lot fitter than when I was younger. He's just got to go back to back now, that's his biggest challenge.

"A lot of defenders underestimate his footwork but that's where he does some damage around the field."

Palu is part of a six-two forwards-backs split on the Waratahs bench as they travel to Canberra for early season bragging rights.

The Waratahs have won five of the past six matches between the teams in an Australian conference domination.

Gibson has no doubt Palu is ready to be thrown into the deep end for his return to the competition.

"I've elected a six-two bench, the reason is we know it's going to be a brutal, physical encounter and I need lots of resources off the bench that I can call on to provide impact," Gibson said.

"For Cliff, it's a perfect situation for him. He's looking particularly menacing at training and he's a physical guy and his spirit and mentality is something we're going to need on Friday night."

The Brumbies have made two changes to their team, with Wallabies prop Scott Sio returning to the starting side and lock Blake Enever replacing last season's rookie of the year, Rory Arnold.

Palu said the Waratahs would not shirk grunt work in the forward pack as they fight fire with fire in the capital.

"We've got the bye next so we can throw everything at the Brumbies, that's a good thing," Palu said.

"These games are won on physicality, they've got a lot of Wallabies players and the only way to get the win is to win up front."

SUPER RUGBY ROUND TWO

Friday: ACT Brumbies v NSW Waratahs at Canberra Stadium, 7.45pm. Tickets available from Ticketek. Curtain-raiser: Brumbies Colts v Next Gen Blues in Super under-20s at 5.15pm.

Brumbies team: 15. Aidan Toua, 14. Henry Speight, 13. Tevita Kuridrani, 12. Matt Toomua, 11. Joseph Tomane, 10. Christian Lealiifano, 9. Tomas Cubelli, 8. Ita Vaea, 7. David Pocock, 6. Scott Fardy, 5. Sam Carter, 4. Blake Enever, 3. Ben Alexander, 2. Stephen Moore, 1. Scott Sio. Reserves: 16. Josh Mann-Rea, 17. Allan Alaalatoa, 18. Les Leuluailii-Makin, 19. Jordan Smiler, 20. Jarrad Butler, 21. Michael Dowsett, 22. Nigel Ah Wong, 23. Andrew Smith.

Waratahs team: 15. Israel Folau, 14. Matt Carraro, 13. Rob Horne, 12. David Horwitz, 11. Zac Guildford, 10. Kurtley Beale, 9. Nick Phipps, 8. Jed Holloway, 7. Michael Hooper, 6. David Dennis, 5. Will Skelton, 4. Dean Mumm, 3. Angus Taavao, 2. Tatafu Polota-Nau, 1. Paddy Ryan. Reserves: 16. Tolu Latu, 17. Matt Sandell, 18. Jeremy Tilse, 19. Sam Lousi, 20. Wycliff Palu, 21. Jack Dempsey, 22. Matt Lucas, 23. Bryce Hegarty.