Marshall pitched a total of 14 seasons in the majors. He was a rookie in Detroit in 1967, appearing in 37 games. He spent all of 1968 in AAA Toledo, with a 15-9 record and a 2.94 ERA. He was then selected by the Seattle Pilots in the expansion draft, and that was the end of Marshall's relationship with the Tigers. Mike Marshall went on to win the Cy Young Award in 1974 and set a major league record the same year with 106 relief appearances.
While still pitching, he earned a Ph.D Kinesiology; which is why he signs his autographs as "Dr. Mike Marshall". Because of his 1968 Topps card, and for being an original Seattle Pilot, his autograph is in demand with collectors. It's a classic case of supply and demand. He rarely signs, so his prices are high. People like me pay those prices because we have a sickness and need to complete our sets!