Closter represented the United States in baseball at the 1964 Summer Olympics. Closter, representing Iowa State University, appeared as one of seven pitchers representing the United States at the Olympics. He was signed by the New York Yankees as an amateur free agent before the start of the 1965 season. \n', '
In 1965, Closter\'s first year in the minor leagues, he split his time between two teams, the Rookie league Johnson City Yankees of the Appalachian League and the single-A Greensboro Yankees of the Carolina League. In the winter, Closter also spent time with the Yankees affiliate of the Florida Instructional League.\n', '
On November 29, 1965, Closter was selected by the Cleveland Indians in the Rule 5 Draft. A few months later, on April 6, 1966, before ever playing a game in the Indians organization, Closter was purchased by the Washington Senators. Closter played only one game in the Senators organization, pitching 0.1 innings against the Baltimore Orioles in his MLB debut, before being purchased again by the Yankees on May 3, 1966.\n', '