South Africa coach Jake White believes the Wallabies lineout has become 'more vulnerable' with the omission of Radike Samo.
White said he was surprised that George Smith had been called up in preference to Samo as the blindside flanker.
Samo's height gave the Wallabies an extra jumping option at the back of the lineout, but coach Eddie Jones has elected to return to the loose forward option he used in 2003.
He has sacrificed height to field twin backrow fliers in Smith and Phil Waugh on the scrum, a decision which White plans to use as a point of attack.
"George Smith, I think obviously they've gone for the combination that played so well in the semi-final of the World Cup, I think that's obviously their thinking," White said.
"I'm a little bit surprised because obviously at lineout time they're going to be a little bit more vulnerable, obviously they have their reasons for playing those two players."
"Maybe it's to slow the ball down at rucks, which those two players are very good at."
"We know Australia, a lot of their attacking plays come from lineouts and we want to put them under pressure at the lineouts."
The Wallabies pack was criticised for its limp performance against New Zealand, and with memories of the last clash with South Africa in Brisbane still fresh, the forward battle is likely to be intense.
White has made only one change to his starting team, which lost 23-21 to New Zealand in Christchurch, with Gerrie Britz returning to replace lock Albert van den Berg.