South Africa captain Warren Whiteley will miss the start of the Rugby Championship and is facing a further six weeks on the sidelines due to the groin injury that brought a premature end to his Super Rugby season.
The talismanic number eight was unavailable for the closing weeks of the Lions' season, which culminated in a 25-17 Super Rugby final defeat to the Crusaders on Saturday.
After that game, the Springboks named a 34-man squad for the start of their Rugby Championship campaign, with Whiteley a notable absentee.
"Warren's absence is a massive blow for the Springboks and for him personally. I really feel for him but I am sure he will get back stronger," said South Africa coach Allister Coetzee.
"It gives an opportunity for another player now and I am sure there will be very strong competition for the number eight jersey."
One of the players in line to stake a claim is Dan du Preez - the brother of Springbok loose forward Jean-Luc du Preez and one of four uncapped players in Coetzee's squad.
Playmaker Curwin Bosch and full-back Warrick Gelant will also hope to make their first senior appearances for the Boks, along with prop Lizo Gqoboka.
South Africa's opening match against Argentina takes place on August 19.
South Africa squad for Rugby Championship:
Forwards: Uzair Cassiem, Lood de Jager, Dan du Preez, Jean-Luc du Preez, Pieter-Steph du Toit, Eben Etzebeth, Lizo Gqoboka, Steven Kitshoff, Siya Kolisi, Jaco Kriel, Frans Malherbe, Malcolm Marx, Bongi Mbonambi, Oupa Mohoje, Franco Mostert, Tendai Mtawarira, Trevor Nyakane, Coenie Oosthuizen, Chiliboy Ralepelle.
Backs: Curwin Bosch, Andries Coetzee, Ross Cronje, Damien de Allende, Warrick Gelant, Francois Hougaard, Elton Jantjies, Jesse Kriel, Dillyn Leyds, Rudy Paige, Handre Pollard, Raymond Rhule, Jan Serfontein, Courtnall Skosan, Francois Venter.