Major League Baseball (MLB) announced eight new rules for the 2020 season back in 2018. Now those rules have been activated.
The biggest rule change is the three batter rule for relief pitchers. In the past, managers would bring out a relief pitcher, usually a lefty to face one batter. Then they would immediately switch pitchers for the next match-up and move on from there. Now this is no longer an option. The rule is an attempt to speed up the game and limit play being stopped on pitching changes. In my opinion, this ruins the strategy of the game and makes it tougher on lefty relievers.