No.8 Alldritt, who captained the side at the Six Nations earlier this year in the absence of skipper Antoine Dupont, has been replaced by RC Toulon's Charles Ollivon for Friday's game at Stade France.
"He (Alldritt) was part of both wins against Japan and New Zealand. He is a captain, he is a leader, an exemplary player and will always be," Galthie said.
"These are choices that are shared internally. There's no controversy around that. There's no controversy about (Matthieu) Jalibert either. He needed to recover and we're talking to him."
Leo Barre, Francois Cros and Uini Atonio have also been named in the starting line-up while the uncapped Marko Gazzotti has earned his first call-up as the 20-year-old makes the bench.
Barre started the win over Japan but was not in the 23-man squad for the 30-29 win over the All Blacks.
However, there was no place for Romain Buros who has not fully recovered from a thigh injury.
"He was honest with us when he said, 'I'm not sure I'll be 100 per cent'. As we can keep only five extra players, we couldn't wait, we had to make a decision and it was Romain who took it," Galthie added.
"I'd like to pay tribute to Romain's courage, honesty and frankness in making this decision."
Argentina thrashed Italy while they narrowly lost to Ireland, and Galthie said the Pumas were having a great season.
"They're not afraid, they're made up of great players who travel to Italy, France and England. They are constantly adapting to the world rugby eco-system," he said.
"It's very intelligent rugby ... It's a very difficult team to play against, one of the best nations in the world."
FRANCE TEAM V ARGENTINA
15-Leo Barre, 14-Gabin Villiere, 13-Gael Fickou, 12-Yoram Moefana, 11-Louis Bielle-Biarrey, 10-Thomas Ramos, 9-Antoine Dupont (capt), 8-Charles Ollivon, 7-Paul Boudehent, 6-Francois Cros, 5-Emmanuel Meafou, 4-Thibaud Flament, 3-Uini Atonio, 2-Peato Mauvaka, 1-Jean-Baptiste Gros: Substitutes: 16-Julien Marchand, 17-Reda Wardi, 18-Georges-Henri Colombe, 19-Alexandre Roumat, 20-Mickel Guillard, 21-Marko Gazzotti, 22-Nolann Le Garrec, 23-Emilien Gailleton.
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