MLB 2023 rule changes: pitch timer, larger bases, shifts

May 09, 2023

Anthony Castrovince

A pitch timer, limits on defensive shifts and bigger bases are coming to Major League Baseball in 2023.

Following recent experiments in the Minor Leagues, the recently formed Joint Competition Committee voted Friday in favor of three rule changes aimed at improving pace of play, action and safety at the MLB level.

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The pitch timer, defensive shift limits and bigger bases were the only three rules proposed by MLB to the Joint Competition Committee -- a voting body consisting of four active players, six members appointed by MLB and one umpire, that was created as part of the 2022-26 Collective Bargaining Agreement. Though the automatic ball-strike system (AKA "robot umps") -- and, alternatively, an ABS challenge system -- has been experimented with in select Minor Leagues this season, a formal rule change proposal related to the ABS has not been made to the committee and is not expected for the 2023 season.

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"We've tried to address the concerns expressed in a thoughtful way, respectful -- always -- of the history and traditions of the game, and of player concerns," Commissioner Rob Manfred said in a press conference Friday afternoon. "Our guiding star in thinking about changes to the game has always been our fans. 'What do our fans want to see on the field?' We've conducted thorough and ongoing research with our fans, and certain things are really clear. Number 1, fans want games with better pace. Two, fans want more action, more balls in play. And three, fans want to see more of the athleticism of our great players.

"The rule changes we're announcing today have been thoroughly tested and refined for years in the Minor Leagues. Each of these rules have been tested in approximately 8,000 Minor League games dating back to last season, which is the equivalent of 3 1/2 complete Major League seasons."

Here are the details of the three rule changes coming to MLB next season:

PITCH TIMER

In an effort to create a quicker pace of play, there will be a 30-second timer between batters. Between pitches, there will be a 15-second timer with the bases empty and a 20-second timer with runners on base. At last check, the pitch timer had reduced the average time of game in MiLB by about 26 minutes. This rule, which includes limits on throws to first base, has also increased stolen-base attempts. With this rule in place in the Minors this season, steal attempts per game have increased from 2.23 in 2019, at a 68% success rate, to 2.83 in 2022, at a 77% success rate.

Note that the rule that will be used in MLB is slightly altered from the rule that was used in MiLB this year. In MiLB in 2022, it was a 14-second timer with the bases empty and 18 seconds (Double-A and lower) or 19 seconds (Triple-A) with runners on, with batters required to be in the box by the 9-second mark and a strict limit of two disengagements per plate appearance (that did not reset if the runner advanced). In its most recent week of play, the Minors have seen an average of .45 violations per game.

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DEFENSIVE SHIFT LIMITS

The defensive team must have a minimum of four players on the infield, with at least two infielders completely on either side of second base. These restrictions are intended to increase the batting average on balls in play, to allow infielders to better showcase their athleticism and to restore more traditional outcomes on batted balls. As of this writing, the league-wide batting average on balls in play of .291 in 2022 is six points lower than in 2012 and 10 points lower than in 2006.

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BIGGER BASES

The bases, which traditionally have been 15 inches square, will instead be 18 inches square. Home plate is unchanged.

Though this can have a modest impact on stolen-base success rate, the primary goal of this change is to give players more room to operate and to avoid collisions. This is especially important at first base, where fielders have an extra 3-inch advantage to stay out of harm's way from the baserunner while receiving throws.

This change will create a 4 1/2-inch reduction in the distance between first and second base and between second base and third, which encourages more stolen-base attempts. The bigger bases could also have the effect of reducing oversliding in which a player loses contact with the bag while sliding through it.