The change at scrumhalf is the only change to their starting team which beat Wales in Cardiff recently, while three players were promoted to the Pumas' bench - prop Carlos Muzzio, scrumhalf Gonzalo Bertranou and utility back Sebastian Cancelliere.
Julian Montoya will lead Argentina against the Springboks at the Nelson Mandela Bay Stadium, where the match is scheduled to start at 17h05.
The Pumas have been in great form recently and beat New Zealand last year, while they crushed a depleted Welsh side by 33-11 last month.
Argentina: 15 Santiago Carreras; 14 Bautista Delguy, 13 Santiago Chocobares, 12 Jeronimo de la Fuente, 11 Matias Moroni; 10 Nicolas Sanchez, 9 Felipe Ezcurra; 8 Rodrigo Bruni, 7 Facundo Isa, 6 Pablo Matera; 5 Marcos Kremer, 4 Guido Petti; 3 Francisco Gomez Kodela, 2 Julian Montoya (captain), 1 Nahuel Tetaz Chaparro. Replacements: 16 Facundo Bosch, 17 Carlos Muzzio, 18 Santiago Medrano, 19 Tomas Lavanini, 20 Matías Alemanno, 21 Gonzalo Bertranou, 22 Domingo Miotti, 23 Sebastian Cancelliere.