Vermaak replaces injured Springbok Cronje
Scrum-half Jano Vermaak replaced the injured Ross Cronje on Sunday when the South Africa squad was named for a Rugby Championship match in Argentina next Saturday.
Cronje won a fitness battle to start in a 37-15 opening round triumph over the Pumas this weekend, but was not at his best.
The 28-year-old Golden Lion is injury prone, missing the final Test in a 3-0 whitewash of France two months ago.
Western Stormer Vermaak debuted for the Springboks in 2013 against Italy in Durban and has been capped three times.
While South Africa were preparing to play Argentina in Port Elizabeth, Vermaak was in Currie Cup action in Cape Town.
The 32-year-old has lined up for the Golden Lions, Northern Bulls, and Toulouse in France, before joining the Stormers.
His competition for a starting place against the Pumas in Salta will come from Francois Hougaard and Rudy Paige.
Hougaard plays for English Premiership club Worcester Warriors and is the only member of the 29-man squad not based in South Africa.
South Africa lie second after the first round, one point behind title-holders New Zealand, who scored eight tries in a 54-34 thrashing of Australia in Sydney.
Eben Etzebeth (capt), Steven Kitshoff, Siya Kolisi, Bongi Mbonambi, Pieter-Steph du Toit (all Western Stormers), Tendai Mtawarira, Coenie Oosthuizen, Daniel du Preez, Jean-Luc du Preez, Chiliboy Ralepelle (all Coastal Sharks), Ruan Dreyer, Jaco Kriel, Malcolm Marx, Franco Mostert (all Golden Lions), Lood de Jager, Trevor Nyakane (both Northern Bulls), Uzair Cassiem (Central Cheetahs)
Andries Coetzee, Elton Jantjies, Courtnall Skosan (all Lions), Jesse Kriel, Rudy Paige, Jan Serfontein (all Bulls), Damian de Allende, Jano Vermaak (both Stormers), Raymond Rhule, Francois Venter (both Cheetahs), Curwin Bosch (Sharks), Francois Hougaard (Worcester Warriors/ENG)
Coach: Allister Coetzee (RSA)