Tom Robertson has been handed a 'dream' Bledisloe start in Sydney, with Scott Sio ruled out with a shoulder injury.

Robertson, who came off the bench in the June Series, will make just his third Test start in the Bledisloe opener after Sio's withdrawal over a shoulder complaint.

Though the Wallabies said at the start of the week Sio had passed a fitness test, he has been unable to shake off a shoulder issue that he aggravated in the side's recent trial.

Robertson's Super Rugby form made it easy for Wallabies coach Michael Cheika to take the cautious route with '50/50' Sio.

"Scott's been battling on and off with his shoulder since I think the last couple of rounds of Super Rugby and I think we finally found deep down there what was giving him the problem," he said.

"Once we knew that, we could make a clearer decision about his return.

"He could do certain things and he couldn't do others and it was 50/50 but I prefer to call it relatively early in the week and give him a chance to get ready for next week and give Tom a chance to prepare well for this week's contest."

Allan Alaalatoa comes onto the bench for the Wallabies after missing the June Series with an injury of his own.

Cheika said Robertson's 2018 had been his best since coming into Super Rugby, with a renewed attitude helping that shift.

"He's only young and coming in on the scene but I think he's had his best year in the pro game by far," he said.

"I think his season with the Waratahs was excellent and in particular in relation to his work ethic.

"He worked real hard to get into position early.

"He's always had a good set piece and he's going to build on that I suppose and he's got a slightly different body shape to our other props, he's a different profile in that way but once he started changing his habits around his work ethic everything started changing for him."

For Dubbo-born Waratah Robertson, a Bledisloe start at ANZ is a 'dream come true' after a childhood spent watching the trans-Tasman battle from afar.

"I (watched) the Bledisloe Cup since I was a kid and to actually be starting in one is a dream come true and I just want Saturday to come quickly," he said.

Robertson said he felt far fitter than he had this time a year ago and set his sights on ensuring that translated into on-field influence.

"As a squad from the Waratahs and Wallabies last year, we weren't fit enough and over the preseason we decided to change," he said.

"I think I'm a lot fitter this year and that's allowed me to do more things on the field and not just have more carries and tackles and whatnot, that doesn't really matter, it's the quality of that involvement.

"That's been my biggest improvement is making them count and hopefully I can get a few of those on Saturday, that'd be great."

Robertson's is the only real surprise in the starting team, with Reece Hodge taking the outside centre position as expected after injuries to Tevita Kuridrani and Samu Kerevi.

Wallabies coach Michael Cheika had no qualms about bringing hooker Tatafu Polota-Nau into the starting spot in his first Test of 2018.

He will be backed up by Tolu Latu, with incumbent Brandon Paenga-Amosa out of the side completely.

Michael Hooper will play his first match since June, named at openside after almost two months out with a hamstring injury.

Matt Toomua is in line to play his first Wallabies Test since the 2016 Bledisloe, named on the bench.

Boom rookie Jack Maddocks pipped Tom Banks for the final bench spot, putting him in line for his Test debut.

The Wallabies host the All Blacks in the first Bledisoe on Saturday August 18, kicking off at 7.45pm AEST, LIVE on FOX SPORTS and via RUGBY.com.au RADIO, with the Wallaroos taking on the Black Ferns from 5:15pm AEST as well. Buy tickets here.

TEAM

Wallabies to face the All Blacks

1. Tom Robertson (21 Tests)

2. Tatafu Polota-Nau (82 Tests)

3. Sekope Kepu (94 Tests)

4. Izack Rodda (7 Tests)

5. Adam Coleman (23 Tests)

6. Lukhan Tui (7 Tests)

7. Michael Hooper (c) (82 Tests)

8. David Pocock (69 Tests)

9. Will Genia (90 Tests)

10. Bernard Foley (58 Tests)

11. Marika Koroibete (11 Tests)

12. Kurtley Beale (74 Tests)

13. Reece Hodge (27 Tests)

14. Dane Haylett-Petty (21 Tests)

15. Israel Folau (65 Tests)

Reserves

16. Tolu Latu (7 Tests)

17. Allan Alaalatoa (23 Tests)

18. Taniela Tupou (4 Tests)

19. Rob Simmons (85 Tests)

20. Pete Samu (3 Tests)

21. Nick Phipps (64 Tests)

22. Matt Toomua (33 Tests)

23. Jack Maddocks*

*denotes uncapped