 Díaz started his career in the Argentine 2nd division with Rosario Central in 1985, after a short spell with Los Andes he returned to Rosario to help the club win the 1986-1987 Primera Division Argentina.His performances earned him a place in the national team and he represented Argentina at the Copa América 1987 and 1989.Díaz joined River Plate in 1989, helping the club to win the 1989-1990 title in his first season he went on to win 8 league titles with the club as well as the Copa Libertadores in 1996 and the Supercopa Sudamericana in 1997.