José Javier Valentín Rosario (born September 19, 1975) is a Puerto Rican former professional baseball catcher.

He made his major league debut on September 13, 1997, and ended up playing three seasons for the Twins.

He remained with the Reds for the five seasons mainly as a back-up catcher and a specialized pinch hitter.

However, on March 28, he was reassigned to minor league camp, declined his assignment, and opted to become a free agent.

On May 14, Valentin signed a minor league deal with the New York Mets and was assigned to Triple-A Buffalo.