The Wallabies were looking to play Scott Sio at tight-head © Getty Images

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Scott Sio has quit the Wallabies squad after rolling an ankle at training on Monday, returning home to Canberra for scans to determine the extent of the injury.

Wallabies management believe he has a syndesmosis injury, and they have replaced him in the squad with Laurie Weeks. The Melbourne Rebels tight-head will join the squad in Bathurst on Wednesday, when the Super Rugby-winning New South Wales Waratahs players will also enter the camp.

Sio plays loose-head, but the Wallabies had plans to train and play the young Brumbies front-rower as a tight-head - hence the decision to select Weeks.

Sio played all five of his Tests off the bench in 2013 - making his debut against the All Blacks in Sydney Bledisloe Cup. Weeks has played two Tests off the bench against France in Melbourne and Sydney this year.

The Wallabies now find the depth of their front row stocks well and truly tested, after hooker Tatafu Polota-Nau was ruled out of the opening Bledisloe Cup game with a knee injury on Monday.

Nathan Charles now is likely to start for Australia against New Zealand, after just two Tests, off the bench against France this year, but Wallabies coach Ewen McKenzie said the Western Force rake was "a very good set-piece player ... an excellent thrower and a very good scrummager".

Benn Robinson, meanwhile, said on Tuesday that he was disappointed to have been overlooked as the replacement for Sio, but McKenzie insisted the veteran Waratahs loose-head was still on his radar.

"Laurie was there and didn't do a bad job for us in June [against France] so we've called him in," McKenzie said. "Robinson has been playing pretty well of late, so he's certainly not out of the picture."