Samu is expected to be left out of the Wallabies squad for games against South Africa and Argentina, leaving a massive hole in the Australian back row for two crucial matches.

Lukhan Tui is also reportedly set to skip the tour and it is unclear whether he will play for the Wallabies again this year after saying he wanted to spend time with his family.

Samu had scans on his knee in Canberra this week after meeting ACT Brumbies staff for the first time. It is hoped it will be fit to play in the third Bledisloe Cup and on the spring tour of Europe.

The duo's absence will mean a forward-pack reshuffle. David Pocock and Michael Hooper are both expected to be fit, while Ned Hanigan and Caleb Timu could compete for the chance to join them in the starting XV.

Samu could make his comeback via the National Rugby Championship if the Wallabies want him to get game time with the Canberra Vikings before the third Bledisloe Cup on October 27.

The Vikings have made five changes to their starting team for a match against NSW Country in Armidale on Sunday, calling on fringe Wallaby Joe Powell and back-row rising star Rob Valetini.

The Vikings will also give teenage playmaker Noah Lolesio a taste of NRC action, with the 18-year-old set to make his debut from the bench.

Wallabies outside centre Tevita Kuridrani is also racing the clock to recover from a torn pectoral in time to be a part of the Australian side's end of year plans.

Injuries to Kuridrani and Samu Kerevi left a gaping hole in the Wallabies midfield for the Rugby Championship, but both could return for the next Bledisloe and the spring tour.

The duo could go head to head in a mouth watering NRC match up if they're both cleared to play in the Vikings clash against Brisbane City on October 14.

Kerevi re-signed with the Queensland Reds on Thursday to stay at the club for at least one more Super Rugby season, despite being linked to a potential move to the Brumbies.

Kerevi has agreed to a one-year extension with the Reds, following the recent re- signings of Izack Rodda, JP Smith, Filipo Daugunu, Chris Feauai-Sautia, Aidan Toua and Alex Mafi.

It means the 24-year-old will be at Ballymore in the lead-up to next year's World Cup.

But the short-term nature of his contract leaves him free to test the open market in 2020 and beyond, with a strike centre of Kerevi's calibre sure to attract big-money offers from Europe and Japan.

"I'm excited to stay in Queensland for one more year. My family was a big factor in staying," Kerevi said.

"The young boys coming through the club is what keeps me at the Reds. I see the potential - not long ago I was in their shoes so to have one more year with them will be special."

Fijian-born Kerevi has scored 21 tries in 58 matches for the Reds, as well as five tries in his 21-Test career for Australia.

Currently sidelined due to a bicep injury, Kerevi hopes to return to fitness towards the end of the NRC season for Brisbane City, with the last game of the regular season to be played against the Vikings.

With AAP

NRC ROUND FOUR

Sunday: NSW Country Eagles v Canberra Vikings at Armidale, 1pm.

Vikings: 1. Sione Taula, 2. Connal McInerney, 3. Tom Ross, 4. Blake Enever, 5. Darcy Swain, 6. Rob Valetini, 7. Michael Oakman-Hunt, 8. Ben Hyne, 9. Joe Powell, 10. Wharenui Hawera, 11. Andy Muirhead, 12. Jordan Jackson-Hope, 13. Irae Simone, 14. Lausii Taliauli, 15. Mack Hansen. Reserves: 16. Josh Mann-Rea, 17. Vunipola Fifita, 18. Max Bode, 19. BJ Edwards, 20. Brodie Leber, 21. Ryan Lonergan, 22. Noah Lolesio, 23. Len Ikitau.