Alan Edward Closter is a former professional baseball pitcher. He pitched parts of four seasons in Major League Baseball between 1966 and 1973, pitching in a total of 21 games.
Closter represented the United States at the 1964 Summer Olympics, where baseball was a demonstration sport. He was signed by the New York Yankees before the beginning of the 1965 season, was drafted from them by the Cleveland Indians before being purchased from them by the Washington Senators before the 1966 season.
Closter was severely injured in a collision with Dallas Green, which derailed his career for some time. He made it back to the majors in 1971 with the Yankees, but never established himself and was out of the majors after 1973.
In 2006, Closter was elected to the Syracuse Baseball Wall of Fame.