The loss of Aphelele Fassi to injury following the record 43-10 rout of New Zealand in Wellington last time out means Damian Willemse switches from inside centre to fullback and is replaced in the No. 12 jersey by De Allende.
Etzebeth comes into the side at lock for Lood de Jager, who was also injured as the Springboks inflicted the heaviest defeat on the All Blacks.
Australia head the Rugby Championship table with 11 points, followed by South Africa and New Zealand on 10 and Argentina on 9 as the teams head into the penultimate round.
"We were very pleased with the way the team rose to the challenge against the All Blacks in Wellington, and looking at the Pumas team and their strengths, we believe this would be the best team for this specific match," Springbok coach Rassie Erasmus said of his selection for Saturday's match.
"They've (Argentina) made big strides in the last few seasons, and have an astute coach in Felipe Contepomi, so we know they are going to throw everything at us.
"Adding to that, they boast a strong forward pack and extremely talented backs, so they pose threats all around."
SOUTH AFRICA v Argentina
15-Damian Willemse, 14-Cheslin Kolbe, 13-Canan Moodie, 12-Damian de Allende, 11-Ethan Hooker, 10-Sacha Feinberg-Mngomezulu, 9-Cobus Reinach, 8-Jasper Wiese, 7-Pieter-Steph du Toit, 6-Siya Kolisi (captain), 5-Ruan Nortje, 4-Eben Etzebeth, 3-Thomas du Toit, 2-Malcolm Marx, 1-Ox Nche
Replacements: 16-Jan-Hendrik Wessels, 17-Boan Venter, 18-Wilco Louw, 19-RG Snyman, 20-Kwagga Smith, 21-Morne van den Berg, 22-Manie Libbok, 23-Andre Esterhuizen
