Pocock has been named to captain the Wallabies for a clash against Samoa on Saturday night, which will likely double as his last Test in Australia.

The champion flanker has played just three games since November last year and hasn't played at all since damaging his calf in a game for the Brumbies in March.

The rare injury prematurely ended his Super Rugby career and threatened his hopes of playing at a third World Cup.

Wallabies medical staff will be nervously watching when he restarts his career, stepping into the leadership role in the absence of Michael Hooper.

A fit Pocock would be a huge boost for the Wallabies' chances of breaking through for their first World Cup title since 1999.

"I'm feeling really good," Pocock said at the World Cup announcement.

"After the training camp [in New Caledonia] I should be ready. I'm getting through everything I need to do before I play.

"A lot of people have gone out of their way [to help with the injury].

"Craig [Purdam] reckons he's retired, but to have someone like him take an interest and spend a lot of time with me figuring it all out ... and Tom Emerson at Praksis. That's the future of where sport will start looking for an edge."

Wallabies coach Michael Cheika has thrown new faces into the Test side to play Samoa as he limits game time for key players before the World Cup campaign begins on September 21.

Powell has missed out, but Tom Banks will start at fullback and Rob Valetini is set to make his international debut from the bench in the match at Parramatta.

Powell was left out of the World Cup squad to play in Japan, but has been the third-choice scrumhalf behind Nic White and Will Genia for every match this year.

White is being rested and Genia will start, but Nick Phipps has surprisingly been parachuted on to the bench ahead of Powell.

It means Powell could play for the Canberra Vikings on Sunday just days after the Wallabies finish a pre-World Cup training camp in New Caledonia.

Powell was arguably the form scrumhalf in Australian rugby during the Super Rugby campaign and helped the Brumbies reach a preliminary final.

Cheika opted to use White and Genia during the Rugby Championships, but Powell has been at every training camp and every Test as the next in line.

Phipps, however, has jumped ahead in the pecking order at the last minute.

MORE RUGBY

Meanwhile, veteran hooker Tatafu Polota-Nau has announced he will retire from international rugby and he will get a chance to farewell fans in the game against Samoa.

"It's awesome to see the depth of hookers in Australian Rugby grow from strength to strength, in particular the gentlemen that have been selected, so much that it's resulted in me missing selection for Japan," Polota-Nau.

"However, I'm pleased that I can contribute by helping to prepare the lads before they take off on their biggest mission.

"I've been very fortunate to wear the gold jersey for as much as I have, and have cherished every single opportunity that I have worn it.

"I want to take this opportunity to thank every person that has been involved with my rugby journey, both in the game and away from it. It's definitely been a privilege to take the field knowing I have represented them to the best of my ability, regardless of the result."

WORLD CUP FAREWELL

Saturday: Wallabies v Samoa at Parramatta Stadium, 7.30pm.

Wallabies: 1. James Slipper, 2. Jordan Uelese, 3. Sekope Kepu, 4. Rob Simmons, 5. Adam Coleman, 6. Lukhan Salakaia-Loto, 7. David Pocock, 8. Jack Dempsey, 9. Will Genia, 10. Bernard Foley, 11. Marika Koroibete, 12. Matt Toomua, 13. Adam Ashley-Cooper, 14. Dane Haylett-Petty, 15. Tom Banks. Reserves: 16. Tatafu Polota-Nau, 17. Scott Sio, 18. Taniela Tupou, 19. Luke Jones, 20. Liam Wright, 21. Rob Valetini, 22. Nick Phipps, 23. James O'Connor.