Paddy Ryan, Nick Cummins, Dominic Shipperley, Ben Tapuai and Pat McCabe have all been selected in a 31-man group that will assemble in Perth on Sunday to prepare for the Springboks clash on September 8.
Cummins and Shipperley have been drafted in to give Deans more options on the wing after Drew Mitchell pulled out with a recurring ankle tendon injury.
Young Queensland Reds forward Jake Schatz has also been left out of the squad because of a shoulder problem.
Australia have lost their opening two matches of the Rugby Championship, going down 27-19 and 22-0 to New Zealand.
McCabe missed those matches after initially being selected by Deans due to a stress fracture in his foot.
Although McCabe has been brought back into the Wallabies' squad, the 24-year-old is still having treatment on his foot and will not be fit until September 15 at the earliest, when Australia tackle Argentina.
The Wallabies are bottom of the standings and desperately need a victory against South Africa to have any chance of challenging for the title.
Adam Ashley-Cooper, Kurtley Beale, Digby Ioane, Dominic Shipperley, Nick Cummins, Rob Horne, Ben Tapuai, Anthony Faingaa, Mike Harris, Pat McCabe, Berrick Barnes, Quade Cooper, Nick Phipps, Will Genia (capt), Scott Higginbotham, Radike Samo, Michael Hooper, Liam Gill, Dave Dennis, Rob Simmons, Nathan Sharpe, Kane Douglas, Caderyn Neville, Sitaleki Timani, Ben Alexander, Paddy Ryan, James Slipper, Benn Robinson, Saia Faingaa, Stephen Moore, Tatafu Polota Nau