An illustrated guide to MLB's new rules in 2023: New pitch clock, bigger bases, no infield shifts

Some of the biggest Major League Baseball rule changes in history roll out in the 2023 season, but they might ultimately be imperceptible to a casual fan – except for a few digital clocks and a little more action on the field.

Of the three major changes, two represent major philosophical shifts. Together all could combine to produce a few more hits, runs and stolen bases and help fans get home a little sooner.

What are baseball's new rules?

  • The bases are a few inches bigger. (More details)

  • Managers are limited in where they position infielders. (More details)

  • A pitch clock will regulate time between the action, which marks a historic trade-off intended to offer more batting than batting glove adjustments.

What are the MLB pitch clock rules?

Umpires track three points throughout a plate appearance: when a batter is ready, when a pitcher begins his delivery and when a batter either reaches base or is called out.

How the MLB pitch clock worked in spring training

According to MLB, the pitch clock results have been encouraging during spring training.

As of March 22, spring training games had been shortened from last year by 25 minutes to 2 hours, 36 minutes, and players have adjusted their approaches to the clock. The number of pitch clock violations fell from two per game in the first week to one per game in the final full week.

Average length of an MLB game in previous seasons

MLB has toyed with speeding games up in recent years. The average length of a game has grown by more than a half-hour in the past 50 years.

MLB set up between-inning clocks that acted more as guidelines than deadlines. The league also directed umpires to expedite visits to the pitcher's mound and limited the number of mound visits to five per team.

Then in 2020, MLB launched the first rule that limits how managers deploy their players. Previously, the final innings could become drawn-out relief pitcher carousels; it's less so now because relief pitchers must face at least three batters – unless they're replaced at the end of an inning.

That was a first step toward restricting a game that's grown longer at the same time our entertainment alternatives have expanded.

Still, players were constrained only by innings and outs, not time.

And while spring training games haven't felt like March Madness with pitchers trying to beat the clock with last-minute buzzer beaters, the clocks ticking down over their shoulders are a clear indication of a new era.

MLB shift rule in 2023

The success of analytics that drove frequent pitching changes also led teams to move their infielders around the field and into the outfield.

In 2015, teams shifted their infield players once every 10 pitches. By last season, the percentage of shifts grew to about a third of all pitches, according to MLB's Statcast database.

Over the same time, offensive production fell. According to Baseball Reference, the league's combined batting average fell from .254 in 2015 to .243 in 2022 as offenses produced 2,431 fewer hits – about one per game.

In 2022, the Dodgers, Blue Jays and Astros shifted their infield players on more than half of the pitches they threw. Colorado shifted the least at 19%, which still amounted to 4,543 pitches.

How often each team shifted infielders during the 2022 season

The new rule requires that infielders stay on their respective sides of the infield and not step onto the outfield grass. Teams aren't even allowed to swap players if, say, they consider their shortstop a better defender than their second baseman. However, teams are allowed to deploy an extra infielder – if they're willing to risk just two players in the outfield.

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New bases are three inches larger

MLB has promoted the larger bases as a safety improvement, saying the larger bases will reduce collisions and have suggested that they might also help to boost offense.

As for safety, MLB says 392 minor league players were injured near bases last year when they tested larger bases – a reduction of five dozen from 2021.

As for offense, minor league players attempted more and stole more bases in 2022. Attempts rose from 2.2 to 2.8 per game, while the success rate jumped from 68% to 78%, according to MLB.

A few inches could also be the difference between a single and an out.

Managers challenged 463 close plays at first last year, winning 289, or 62%, of them, according to MLB's Statcast database. With first base 3 inches closer to home, how many of those calls would have been easier and how many more would have been called into question?

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All of these changes have been tested in 8,000 minor league games, MLB says.

The results: Beyond higher steal rates, nine-inning games were shortened by 25 minutes (pitch clock), and batting averages ticked up a couple of points (no infield shifts).

This article originally appeared on USA TODAY: MLB rule changes 2023: Guide to pitch clock, bases, banning the shift