What is the MLB 3-batter rule?

The MLB instituted a controversial 3-batter rule that fans are leaning more about in the 2021 postseason. Here’s more on the rule and how it could shape any MLB game.

In its 152-year history, the MLB has undergone countless changes. One of its more recent changes, though, can greatly influence the outcome of a game if the wrong pitcher is in.

MLB’s 3-batter minimum rule, which came into play in 2020, mandates pitchers to “either face a minimum of three batters in an appearance or pitch to the end of a half-inning, with exceptions for injuries and illnesses.”

The rule was created to reduce the number of pitching changes in an attempt to cut down the length of MLB games, which only goes up as the years go on. In 2021, the average length of an MLB game was three hours, 10 minutes and seven seconds, which is a new all-time high. 2021 is the third consecutive year in which gameplay has reached an all-time high, meaning that the 3-batter rule has been ineffective in reducing game time.

While the upside was intended to be a reduced gametime, the downside is that when a pitcher is doing poorly, they cannot be substituted until they’ve seen at least three batters. This created a disastrous situation when St. Louis Cardinals pitcher Génesis Cabrera was pitching wildly in an April 28 game against the Philadelphia Phillies.

Because Cabrera could not be substituted, he ended up slamming Bryce Harper in the face with a 96.9-mph fastball. Cabrera then hit the next batter, Didi Gregorius, with a 94.5-mph pitch. At the time, Cardinals manager Mike Shildt told media that he would’ve pulled Cabrera immediately after the Harper hit if it were allowed — but it wasn’t because of the 3-batter rule.

When the stakes are high in a Series game or even during the regular season, the 3-batter rule is one that, for better or for worse, drastically shapes the control any manager has over the game.