Major League Baseball (MLB) is the highest level of play in North American professional baseball. Founded in 1869, it is composed of 30 teams. Each team in the league has a manager, who is responsible for team strategy and leadership on and off the field. Assisted by various coaches, the manager sets the line-up and starting pitcher before each game, and makes substitutions throughout the game. In early baseball history, it was not uncommon for players to serve as player-managers; that is, they managed the team while still being signed to play for the club. In the history of MLB, there have been 221 player–managers, 59 of whom are in the National Baseball Hall of Fame.