Donald Arthur Mattingly is an American professional baseball coach, and former first baseman and manager in Major League Baseball (MLB). He is the bench coach for the Toronto Blue Jays of MLB. Nicknamed "the Hit Man" and "Donnie Baseball", he spent his entire 14-year MLB playing career with the New York Yankees and later managed the Los Angeles Dodgers for five years and the Miami Marlins for seven years.

In baseball, a number of coaches assist in the smooth functioning of a team. They are assistants to the manager, who determines the starting lineup and batting order, decides how to substitute players during the game, and makes strategy decisions. Beyond the manager, more than a half dozen coaches may assist the manager in running the team. Essentially, baseball coaches are analogous to assistant coaches in other sports, as the baseball manager is to the head coach.