[1][2] After graduating from high school, Zepp declined the opportunity to play professional baseball and instead enrolled at the University of Michigan.

[4] After receiving his degree, Zepp sought to pursue his dream of playing Major League Baseball, but most clubs were not interested in a 22-year-old rookie.

[3] During the winter following the 1968 season, Zepp played in the Florida Instructional League where he worked on developing a changeup pitch and led the circuit with a 1.14 ERA.

However, in a move that reportedly infuriated Martin, the club's management instead assigned Zepp to play Single-A ball with the Red Springs Twins in the Carolina League.

Zepp made two short relief appearances in the 1970 American League Championship Series against the Baltimore Orioles, giving up two hits and one run in one inning.

Prior to the 1971 season, Zepp refused to sign a contract extension with the Twins and stated that he intended to retire from baseball unless he were traded to the Detroit Tigers, his hometown club.

[8] Zepp later recalled that he had suffered a "Tommy John injury", tearing a tendon and resulting in lost arm strength.