Mark Anthony Eichhorn (born November 21, 1960, in San Jose, California) is a retired Major League Baseball pitcher best known for his tenure with the Toronto Blue Jays in the late 1980s and the early 1990s when he often served as a middle reliever/set-up man for All-Star closer Tom Henke.
He was the 1986 American League Rookie Pitcher of the Year for the Blue Jays, a campaign in which he set team records for rookie relief in ERA, games, wins, and strikeouts.