MLB will implement a “Three Batter Minimum” rule for relief pitchers in 2020. The intent of the change is to cut down the length of games and avoid numerous pitching changes in the same inning.
The new rule states that; pitchers will be required to either face a minimum of three batters or pitch to the end of a half-inning, with exceptions to be made in case of injury or illness. Previously, pitchers were required to pitch to only one batter and once the hitter had been retired or reached base safely, the pitcher could then be removed from the game.