Mark Philip Schaeffer (June 5, 1948 – June 1, 2022) was an American professional baseball player. He played in Major League Baseball as a left-handed pitcher for the San Diego Padres in 1972. He batted and threw left-handed. Schaeffer was strictly a relief pitcher in MLB (41 appearances, zero starts). On July 29, 1972, during a 17 inning, 4–3 victory over the Reds, Schaffer picked up his lone MLB save by retiring the final batter of the game. Schaeffer died June 1, 2022.