The 2019 season brought significant changes to MLB, including the elimination of the August waiver trade deadline and less time in between innings.
An additional set of new rules will be introduced during the 2020 season. Arguably the most notable change is that pitchers are now required to either face a minimum of three batters or reach the end of a half-inning (with exceptions for incapacitating injury or illness).
The rule was first discussed last offseason, along with the implementation of a universal designated hitter and roster expansion. While the DH will remain exclusively in the American League for the 2020 season, rosters are set to expand to 26 players next year.