Major League Baseball has instituted a series of rule changes for the 2020 season, led by a three-batter minimum for relief pitchers.
The official release from MLB lists eight new rules or changes to existing rules, including increasing the active roster size through Aug. 31 and the postseason from 25 to 26 players and increasing mandatory time on the injured list for pitchers from 10 to 15 days.
MLB and the MLB Players Association agreed to roll out a number of rule changes over a two-season period starting in 2019.
The biggest change for teams is the adoption of a three-batter minimum for all pitchers. It's designed to decrease the amount of game time, but there are possible ramifications for teams that will significantly alter in-game strategy for managers.
For instance, Cleveland Indians reliever Oliver Perez is a left-handed pitcher who was used specifically to get out left-handed hitters for opposing teams last season. He only faced three batters in a game 34 times in 67 appearances last season. Right-handed hitters posted an .889 OPS against him in 2019; lefties had a .607 OPS in 95 plate appearances.
Increasing the amount of time pitchers spend on the injured list is designed to prevent teams from manipulating their rosters. The Los Angeles Dodgers were particularly adept at using the 10-day timeframe to their advantage in order to get their wealth of starting pitchers into games during the 2017 season.
September roster increases still exist, but now teams are only allowed to carry a maximum of 28 players instead of up to 40.
Two-way players, like Shohei Ohtani of the Los Angeles Angels, won't count against the new 13-pitcher maximum that teams are allowed to carry. Teams have to designate a two-way player as such prior to the first pitch of a game.
MLB will also mandate that position players are only allowed to pitch in extra innings or if their team is losing by at least six runs. Managers will also now have only 20 seconds in which to initiate a challenge rather than 30.
The 2020 MLB regular season will begin on March 26 with all 30 teams playing.