Pichot has been ruled out of head coach Marcelo Loffreda's starting line-up due to a knee injury.
Nicolas Vergallo will take his place in the 15, while Patricio Albacete will take over the captain's armband.
Santiago Gonzalez Bonorino is set to make his first Pumas appearance since 2003.
He said: "I never closed the doors to the national team and I've always imagined a return to the Pumas.
"I'm really enjoying my return and I hope to profit from this opportunity."
Argentina starting line-up:
Federico Serra; Ignacio Corleto, Martin Gaitan, Hernan Senillosa, Rafael Carballo; Juan de la Cruz Fernandez Miranda, Nicolas Vergallo; Genaro Fessia, Lucas Ostiglia, Agustin Creevy; Jaime Arocena, Patricio Albacete (captain); Santiago Gonzalez Bonorino, Pablo Gambarini, Rodrigo Roncero.
Replacements: Juan Gomez, Alberto Vernet Basualdo, Rimas Alvarez, Federico Genoud, Lucio Lopez Fleming, Horacio Agulla, Juan Martin Hernandez.