Mark Stephen DeJohn (born September 18, 1953) is an American professional baseball coach and former infielder and manager. A switch hitter who threw right-handed, DeJohn stood 5 feet 11 inches (1.80 m) tall and weighed 170 pounds (77 kg). A former shortstop, DeJohn was chosen by the New York Mets in the 23rd round of the 1971 amateur draft after his graduation from Woodrow Wilson High School in Middletown. He spent seven years in the Mets farm system, including three with the Triple-A Tidewater Tides, before becoming a free agent before the 1978 season.