Stephen Larkham will get 'burnt to a crisp' if he keeps dual role, says Wallabies coach Michael Cheika

Larkham is back in Wallabies camp after agreeing to a one-year contract extension with the Brumbies, but the World Cup-winner will make a decision on his long-term future in the coming months.

Larkham is weighing up an offer from the ARU to become a full-time Wallabies assistant coach until the 2019 World Cup, but the Brumbies want to keep him as the man in charge in Canberra.

His immediate job is helping engineer a Wallabies revival for a crucial Test against South Africa in Brisbane on Saturday night.

But Larkham wants to finalise his coaching future as soon as possible to give the Brumbies and the Wallabies a chance to find a replacement depending on his choice.

Cheika recruited Larkham as his backline expert when he started in Australia's top job and both men juggled Super Rugby roles with Wallabies duties last year.

"If you do both for that many years you'll be burnt to a crisp," Cheika said.

"It was always the intention Stephen would do another year at the Brumbies, that's the idea.

"What decision he makes after that will be up to him, but we're very keen to keep this group of coaches together all the way through so we can start building a solid base.

"Then develop other coaches through Super Rugby that are ready to take on those [Wallabies] positions further down the track and actually build something for the future.

"All the things in front of us are very important as well, but it's naive if we don't prepare for the future because maybe we haven't done that in the past," he said.

Cheika axed Brumbies back-rower Scott Fardy from his side on Thursday, promoting Dean Mumm to the starting XV to play the Springboks.

The Wallabies have struggled in their opening Tests of the Rugby Championships, losing twice to New Zealand.

Their losing run is compounded by their three-Test series defeat at the hands of England in June and Cheika is searching for combinations to add spark to the line-up.

Tevita Kuridrani and giant lock Rory Arnold have been added to the Wallabies bench, while Henry Speight will rejoin the Canberra Vikings to get game time before making his Test comeback.

Cheika said Mumm's lineout accuracy tipped him ahead of Fardy at the selection table.

A perceived lack of height in the back row did not come into calculations, with Mumm (196cm) standing two centimetres shorter than Fardy.

"I think he's played well when he's come off the bench in both matches and he's finished for us well, shown a lot of energy and deserves an opportunity," Cheika said.

When asked about Fardy's axing, Cheika said: "Maybe a game off will give him the chance to freshen up and get himself fired-up to come back."

Reece Hodge will start on the wing in place of Adam Ashley-Cooper and Cheika plans on using him as a long-range kicking weapon after he landed a 55-metre monster two weeks ago.

"He gives a bit more versatility around how we want to set the team up attacking and defensively," said Cheika of Hodge, who made his debut off the bench in Wellington.

"And I just like the way he's played. I think he's got good composure, good demeanour and the more experience we get him in these big matches the better he'll be going forward."

RUGBY CHAMPIONSHIPS

Saturday: Wallabies v South Africa at Suncorp Stadium, 8.05pm. TV time: Live on Fox Sports 2.

WALLABIES TEAM

1. Scott Sio (20 Tests)

2. Stephen Moore (c) (107 Tests)

3. Sekope Kepu (68 Tests)

4. Kane Douglas (25 Tests)

5. Adam Coleman (2 Tests)

6. Dean Mumm (48 Tests)

7. Michael Hooper (56 Tests)

8. David Pocock (58 Tests)

9. Will Genia (68 Tests)

10. Quade Cooper (59 Tests)

11. Reece Hodge (1 Test)

12. Bernard Foley (32 Tests)

13. Samu Kerevi (3 Tests)

14. Dane Haylett-Petty (5 Tests)

15. Israel Folau (43 Tests)

Reserves (one to be omitted)

Tatafu Polota-Nau (66 Tests)

James Slipper (79 Tests)

Allan Alaalatoa (2 Tests)

Rory Arnold (2 Tests)

Lopeti Timani (possible debut)

Sean McMahon (9 Tests)

Nick Phipps (44 Tests)

Tevita Kuridrani (36 Tests)

Drew Mitchell (70 Tests)