Contepomi played in Argentina's tour games against France and Italy
Argentina coach Santiago Phelan has made five changes to his starting line-up for Saturday's Test against Ireland.
Captain Felipe Contepomi misses out because of a hand infection with Miguel Avramovic coming in at inside centre.
Federico Martin Aramburu switches to outside centre with Francisco Leonelli taking his place on the right wing.
Horacio Agulla moves to full-back, Rimas Alvarez Kairelis is at lock, while Juan Manuel Leguizamon comes in
at number eight.
Juan Martin Fernandez Lobbe moves to the open-side flank with the Sale forward also taking over from Contepomi as skipper.
Contepomi, who plays his club rugby with Leinster, suffered a cut to his hand prior to Argentina's European tour but the injury has now become infected.
"Because of this infection, he underwent a drainage and cleaning at St Vincent's University Hospital," said Pumas doctor Guillermo Botto.
Despite picking up the cut before the first game of the tour, Contepomi still started the 12-6 defeat in France on 8 November and the 22-14 win against Italy a week later.
The game has huge significance for Ireland as they need to defeat the Pumas or could be overhauled by Scotland for a second-tier World Cup seeding.
Argentina: Agulla (Brive); Leonelli (Saracens), FM Aramburu (Dax), Avramovic (Montauban), Carballo (Castres); Hernandez (Stade Francais), Vergallo (Dax); Roncero (Stade Francais), Ledesma (Clermont Auvergne), JP Orlandi (Rovigo), Alvarez (Perpignan), Albacete (Stade Toulouse), Durand (Champagnat), JM Fernandez Lobbe (Sale Sharks, capt), JM Leguizamon (Stade Francais).
Replacements: Basualdo (Stade Toulouse), Ayerza (Leicester), Lozada (Toulon), Galindo (Racing Metro), Figuerola (CASI), Fernandez (Hindu), Stortoni (Glasgow).