Castrogiovanni was banned for two weeks after appearing to direct a stamp towards Scotland's Duncan Taylor in a 36-20 loss in Rome.
Injured centre Michele Campagnaro is replaced by Andrea Pratichetti.
Tommason Allan comes in at number 10 for fly-half Edoardo Padovani.
Italy, captained by Sergio Parisse, are without a number of key players through injury, including Campagnaro and Padovani.
Wales lie second ahead of the match at the Principality Stadium, while Italy are bottom of the table following four defeats.
Italy starting side: Odiete; L Sarto, Pratichetti, Garcia, Bellini; Allan, Palazzani; Lovotti, Giazzon, Castrogiovanni; Geldenhuys, Bernabo; Minto, Zanni, Parisse.
Replacements: Fabiani, Zanusso, Chistolini, J Sarto, Steyn, Lucchese, Haimona, McLean.
Italy have made five changes for Saturday's Six Nations match in Wales as veteran prop Martin Castrogiovanni returns from suspension after missing last weekend's 58-15 loss to Ireland.