Stade Francais fly-half Juan Martin Hernandez is sidelined with a thigh injury, so Felipe Contepomi takes the number 10 jersey, switching from inside centre.
Only three forwards remain from the 33-3 victory over Georgia with Patricio Albacete, Juan Martin Fernandez Lobbe and Juan Manuel Leguizamon retaining their places.
Federico Todeschini, whose World Cup was in doubt because of a calf injury, is on the bench and, in total, there are nine changes from the team that defeated Georgia.
Leguizamon joked that he wanted Ireland to beat France and guarantee them a spot in the knock-out stages.
Namibia coach Hakkies Husselman has made 10 changes from the side beaten 87-10 by France for the match against Argentina.
Injured skipper Kees Lensing is ruled out as the African side look beyond Argentina at a morale-boosting win over Georgia in their final group game in Lens on September 26.
“I think we really need to rest some players. We can’t play at this level three times in a row, especially with matches so close together,” said Husselman, the youngest coach at the World Cup at 34 years of age. Centre Corne Powell takes over the captaincy from Lensing.
Husselman admitted that he had one eye on the wooden-spoon game against Georgia.
“We will try to beat Argentina but they are a professional team, a tier-two nation and many of their players play in France.
I Corleto; H Senillosa, G Tiesi, M Contepomi, H Agulla; F Contepomi, A Pichot (captain); R Roncero, AV Basualdo, O Hasan, C Fernandez Lobbe, P Albacete, L Ostiglia, JM F Lobbe, J Leguizamon.
M Ledesma, JM Scelzo, R Kairelis, G Longo, N Fernandez Miranda, F Todeschini, F Miras.