Franco Mostert and Ox Nche have been ruled out of the Springboks' upcoming Test against Argentina, head coach Rassie Erasmus confirmed ahead of Saturday's squad announcement.
The pair join long-term absentees Kwagga Smith and RG Snyman on the sidelines, with Erasmus set to name a 26-man travelling party for the Buenos Aires fixture. Ntuthuko Mchunu has been recalled to cover for Nche at prop.
Erasmus indicated that players who featured heavily in the URC and the opening three Tests against England, Scotland and Wales will remain in the Republic to begin preparations for the All Blacks series. Pieter-Steph du Toit, who captained the side during the Nations Championship, headlines that group.
Several established Springboks will make the trip to South America, however. Eben Etzebeth, Lood de Jager, Siya Kolisi, Sacha Feinberg-Mngomezulu, Ethan Hooker, Canan Moodie and Andre Esterhuizen are all fit and expected to be involved against Los Pumas.
Erasmus told media that the selection policy was straightforward. "The guys who need game time will go to Argentina," he said, adding: "You do the math."
Cobus Reinach will start at scrum-half with Morné van den Berg on the bench, while Aphelele Fassi is set for another opportunity at fullback. Edwill van der Merwe looks likely to feature on the wing, with Cheslin Kolbe among those staying home.
Handre Pollard's involvement remains dependent on his recovery from a hamstring strain, with Vusi Moyo on standby should any doubt remain over the fly-half's fitness.
The Springboks face Argentina before returning to host New Zealand in the Rugby's Greatest Rivalry series, which begins with the All Blacks' tour match against the Stormers in Cape Town on 7 August.