The Springboks believe the revamp of the Australian pack shows the Wallabies still have concerns over the fitness of their lineout chief Nathan Sharpe.

Sharpe injured his ankle in last weekend's loss in Pretoria but completed Australia's second training session this week and has declared he is ready for Saturday's (0100 Sunday AEST) Tri-Nations Test in Bloemfontein.

Crucially, the Wallabies lineout suffered in Western Force captain Sharpe's absence when he was forced from the field.

Coach Robbie Deans named experienced lock Mark Chisholm and hooker Stephen Moore and lineout option Ben McCalman at No.8 ahead of Dean Mumm, Saia Faingaa and Richard Brown for this weekend's clash.

"I think they're slightly worried about Sharpie," South Africa forwards coach Gary Gold said.

"They lost a lot of cohesion when he went off in the second half last week.

"Ben (McCalman) is a better lineout option than Richard Brown and up front the selection of Stephen Moore suggests they'll want to match us for experience."

The Boks expect Australia to come at them with muscle, believing the changes could mark a partial departure from the wide game adopted in both the 30-13 Australian win in Brisbane and 44-31 near miss at Loftus Versfeld.

"We're expecting them to be a bit more direct," Boks assistant Dick Muir said.

"If you look at their selection changes, they'll try to muscle up to us and be more physical."

But the South Africans say that could also allow Wallabies playmakers Will Genia and Quade Cooper to wreak havoc.

"Those players can be so lethal, but if we focus on the individual, it can open up space for other players," Gold said.

"We have to back our systems and guys need to trust the men outside them.

"A guy like Cooper has a fantastic step and puts team-mates into holes, but we've got to work as a unit to stop that."

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