Kinzer, a native of Markle and graduate of Norwell High School, played six seasons of professional baseball, including two one-year stints with the St. Louis Cardinals (1989) and the Detroit Tigers (1990). He made his MLB debut on May 18, 1989 for the St. Louis Cardinals, pitching 3.1 innings, giving up one hit and striking out three versus the Houston Astros. Elbow surgery forced Kinzer to retire in 1990. His major league totals were nine appearances, an 0-2 record and a 13.20 ERA. He also played one NFL game as a punter for the Detroit Lions during the 1987 strike.