There was no place for 2019 and 2023 World Cup winners Lukhanyo Am, Faf de Klerk and Makazola Mapimpi when coach Rassie Erasmus released his squad on Wednesday.
The experienced trio are on a stand-by list in case of injury as Erasmus named a 37-player group to meet the Wallabies in Johannesburg on August 16 and in Cape Town a week later.
Recent new caps Ethan Hooker (utility back), Asenathi Ntlabakanye, Boan Venter (both props), Marnus van der Merwe (hooker) and Cobus Wiese (utility forward) have all been included.
Bath prop Thomas du Toit has been granted a compulsory two-week rest as agreed with the English Premiership, while number eight Jasper Wiese, the brother of Cobus, is serving a four-week suspension.
Erasmus has already used almost 50 players in three Tests this year as he looks to add depth to the squad with the 2027 Rugby World Cup in mind.
"It's always challenging to reduce the squad, especially given how the expanded group of players put up their hands (in wins over Italy and Georgia this month), but we always said we would select a smaller, more manageable squad during the Rugby Championship," Erasmus said.
"We probably have three players who can cover each position. One of our key pillars as a team is to build squad depth, and there is no better way to see what some of the younger players are capable of than to expose them to some of the top teams in the world."
The Springboks have also invited three players from South Africa's victorious side at the recent Under-20 World Cup to train with the team to gain experience.
They are loose-forward Bathobele Hlekani, wing Cheswill Jooste and scrumhalf Haashim Pead.
SOUTH AFRICA SQUAD:
Forwards: Lood de Jager, Pieter-Steph du Toit, Jean-Luc du Preez, Eben Etzebeth, Vincent Koch, Siya Kolisi, Wilco Louw, Malcolm Marx, Bongi Mbonambi, Franco Mostert, Ox Nche, Ruan Nortje, Asenathi Ntlabakanye, Kwagga Smith, RG Snyman, Marnus van der Merwe, Marco van Staden, Boan Venter, Jan-Hendrik Wessels, Cobus Wiese
Backs: Kurt-Lee Arendse, Damian de Allende, Andre Esterhuizen, Aphelele Fassi, Sacha Feinberg-Mngomezulu, Ethan Hooker, Jesse Kriel, Cheslin Kolbe, Willie le Roux, Manie Libbok, Canan Moodie, Handre Pollard, Cobus Reinach, Edwill van der Merwe, Morne van den Berg, Grant Williams, Damian Willemse
