 Matosas made his debut in 1985 playing for Peñarol in Uruguay, with whom he won the Copa Libertadores in 1987, as well as two league titles, and went on to play for Málaga in Spain, San Lorenzo in Argentina, São Paulo in Brazil, Tianjin Teda in China, as well as having brief stints with other clubs in Argentina, Brazil, and Spain before retiring in 2001, last playing for Querétaro of the Mexican Primera División.An Uruguayan international, Matosas gained his first cap in 1987.That year, he won the Copa América title with Uruguay after defeating Chile 1–0 in the Final.