Federico, the son of former Real Madrid player Fernando Redondo, has joined the MLS club Inter Miami.
The 21-year-old midfielder played 44 matches in the past season, scoring two goals and providing two assists in all competitions.
The Argentine becomes a teammate of Lionel Messi, Luis Suarez, Jordi Alba, and Sergio Busquets, moving from Argentinos Juniors for €7.4 million. Redondo's contract runs until 2027.
Previously, Luis Suarez stated that joining Inter Miami was his top ambition. It is also reported that the Florida club urgently needs to reduce its salary expenditures.