Castrogiovanni returns t the starting XV after appearing as a replacement in the opening autumn Test against Tonga last weekend as Italy make eight changes to the line-up to face the world champions.
Marcos Ayerza starts for Argentina in their clash with France in Lille on Saturday.
The Leicester Tigers prop wins his 39th Test cap as the Pumas make three changes to the side that beat Wales last weekend.
Former Tigers players Lucas Amorosino and Horacio Agulla come in for Juan Martin Hernandez and Gonzalo Camacho respectively, while Marcelo Bosch replaces the injured Felipe Contepomi at centre.
Tigers' Vereniki Goneva wins his 28th cap for Fiji this weekend, playing at centre in the match against ireland after also starting last week's opening Test against England at Twickenham.