Geronimo Prisciantelli comes into the fullback position in the place of Carreras and makes up a back three with wings Ignacio Mendy and Rodrigo Isgro.
Faustino Sanchez Valarolo and Lucio Cinti are the centre-pairing, with Simon Benitez Cruz at scrumhalf.
Ignacio Ruiz has been selected at hooker and will have props Boris Wenger and Francisco Moreno either side of him. Guido Petti and Tomas Lavanini are the lock pairing.
Pablo Matera and Benjamin Grondona are the two flankers, with Joaquin Moro at number eight.
Hooker Leonel Oviedo, loose forward Juan Penoucos and prop Juan Martin Scelzo could all make their debuts off the bench against the four-time world champions.
Argentina are without several regular players, who are either injured or have returned to their European clubs for pre-season training.
Argentina team:
Starters: 15-Geronimo Prisciantelli; 14-Rodrigo Isgro, 13-Lucio Cinti, 12-Faustino Sanchez Valarolo, 11-Ignacio Mendy; 10-Santiago Carreras, 9-Simon Benitez Cruz; 8-Joaquin Moro, 7-Benjamin Grondona, 6-Pablo Matera (capt); 5-Tomas Lavanini, 4-Guido Petti; 3-Francisco Moreno, 2-Ignacio Ruiz, 1-Boris Wenger
Replacements: 16-Leonel Oviedo, 17-Mayco Vivas, 18-Tomas Rapetti, 19-Efrain Elias, 20-Juan Penoucos, 21-Juan Martin Scelzo, 22-Agustin Moyano, 23-Matias Moroni
South Africa team:
Starters: 15-Aphelele Fassi; 14-Edwill van der Merwe, 13-Canan Moodie, 12-Andre Esterhuizen, 11-Ethan Hooker; 10-Sacha Feinberg-Mngomezulu, 9-Cobus Reinach; 8-Cameron Hanekom, 7-Elrigh Louw, 6-Siya Kolisi (capt); 5-Lood de Jager, 4-Eben Etzebeth; 3-Thomas du Toit, 2-Johan Grobbelaar, 1-Boan Venter
Replacements: 16-Jan-Hendrik Wessels, 17-Gerhard Steenekamp, 18-Zachary Porthen, 19-Ben-Jason Dixon, 20-Cobus Wiese, 21-Marco van Staden, 22-Morne van den Berg, 23-Handre Pollard