Michalak will return to France next season with Toulon, and Saint-André admits his ability to cover both the scrum-half and fly-half roles played a part in his return.
"He had a very good game last time out for the Sharks," said Saint-André. "He knows the top level and can play at nine and ten.
"What's more, he is returning to France next season and having spoken to him on the phone I can assure you he is very motivated and has done everything he can to get back into the squad.
"We need players with huge potential and a lot of charisma, it was only natural that he be recalled."
Michalak is only one of a much-changed French squad, with nine uncapped players among the 28 selected by Saint-André.
Skipper Thierry Dusautoir is also being rested, so Stade Français second row Pascal Papé will captain the side in the two tests against the Pumas.
Toulouse hooker Christopher Tolofua could make his debut aged only 18, while Antoine Guillamon, Yvan Watremez, Christophe Samson and Romain Taofifenua are also novices in the pack.
In the backline Maxime Machenaud, Geoffrey Doumayrou, Romain Martial and Brice Dulin could also make their debuts while wingers Benjamin Fall and Yoann Huget also make their returns from injury and a drugs ban respectively.
Forwards: Attoub (Stade Français), Debaty (Clermont), Guillamon (Lyon), Watremez (Biarritz), Tolofua (Toulouse), Szarzewski (Stade Français), Samson (Toulon), Maestri (Toulouse), Papé (Stade Français), Taofifenua (Perpignan), Lapandry (Clermont), Lauret (Biarritz), Ouedraogo (Montpellier), Picamoles (Toulouse), Lakafia (Biarritz)
Backs: Machenaud (Agen), Parra (Clermont), Michalak (Sharks), Trinh-Duc (Montpellier), Doumayrou (Montpellier), Fritz (Toulouse), Fofana (Clermont), Mermoz (Perpignan), Fall (Racing), Martial (Castres), Huget (Bayonne), Buttin (Clermont), Dulin (Agen)