Messi's Argentine compatriot Cristian "Kily" Gonzalez will take over the reigning champions in Major League Soccer, the North American professional league, as soon as the 52-year-old receives his work permit.
Gonzalez, who hails from Messi's hometown of Rosario, earned 56 caps for Argentina between 1995 and 2005, playing for clubs including Inter, Valencia and Zaragoza.
Inter Miami, who signed Casemiro from Manchester United this summer, is second in the Eastern Conference, 10 points behind leaders Nashville.
Guillermo Hoyos has been in temporary charge in Miami since Javier Mascherano left in April for personal reasons.
