Atlantic League of Professional Baseball (ALPB)

5 MLB Rule Changes That Were Tested In The Atlantic Baseball League

5 MLB Rule Changes That Were Tested In The Atlantic Baseball League

Major League Baseball made rule changes that will change how the game is played. Many of those rules were tested in the Atlantic Baseball League

May 11, 2023 by Joe Harrington
5 MLB Rule Changes That Were Tested In The Atlantic Baseball League

The 2023 version of Major League Baseball looks very different than all the years that came before it and the Atlantic League has something to do with it. 

Since 2019, the Atlantic League has partnered with MLB to experiment on rule changes for America’s past time. 

Some of those rules were implemented when the 2023 baseball season began in April (and some weren’t). 

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The rules have caused a quicker baseball game to be played, with game times down by about an average of 30 minutes. It has also caused more stolen bases, and if some of the current rules that are being tested come to light in the MLB, there could be even more stolen bases. 

Here are 5 MLB Rule Changes that were tested in the Atlantic Baseball League. 

1. The Pitch Clock

The pitch clock, which times the seconds between pitches thrown, was tested as early as 2010 in college baseball. Minor League baseball adopted the pitch clock in 2014 during the Arizona Fall League, and Double-A and Triple-A baseball adopted the 20-second pitch clock in 2015.

The Atlantic League began using a 12-second pitch clock in 2015. 

MLB split the difference this season when it adopted the pitch clock. Instead of 20-seconds or 12-seconds, MLB uses 15-seconds between pitches. That time increases to 20-seconds if there are runners on base. 

Need more? Here’s what the MLB rules also say: 

  • The pitcher must begin his motion to deliver the pitch before the expiration of the pitch timer.
  • Pitchers who violate the timer are charged with an automatic ball. Batters who violate the timer are charged with an automatic strike.
  • Batters must be in the box and alert to the pitcher by the 8-second mark or else be charged with an automatic strike.
  • With runners on base, the timer resets if the pitcher attempts a pickoff or steps off the rubber.
  • Pitchers are limited to two disengagements (pickoff attempts or step-offs) per plate appearance. However, this limit is reset if a runner or runners advance during the plate appearance.
  • If a third pickoff attempt is made, the runner automatically advances one base if the pickoff attempt is not successful.
  • Mound visits, injury timeouts and offensive team timeouts do not count as a disengagement.
  • If a team has used up all five of its allotted mound visits prior to the ninth inning, that team will receive an additional mound visit in the ninth inning. This effectively serves as an additional disengagement.
  • Umpires may provide extra time if warranted by special circumstances. (So if, as an example, a catcher were to be thrown out on the bases to end the previous half-inning and needed additional time to put on his catching gear, the umpire could allow it.)

2. The 3-Batter Minimum 

The three-batter minimum rule went into effect in 2020 even before some temporary rules were put in place due to the COVID-19 pandemic. This included the three-batter minimum that the Atlantic League tested the prior season. 

For years managers, most notably Hall of Famer Tony La Russa, would make multiple pitching changes in an inning. A left-handed pitcher would enter to face a left-handed batter, and be removed from the game after that batter. 

No more. 

The time consuming pitching changes were done away with and teams can only make pitching changes after the pitcher faces three batters (unless an injury occurs) or between innings. If a pitcher returns in the next inning, he can be removed before facing three batters.

3. Wider bases

It may seem like a small change, but it has become quite big in baseball. It’s simple: the larger the base, the easier it can be stolen. 

The Atlantic League began using bigger bases in 2019, the same year the MLB agreement started. Bases went from 15 inches to 18 inches. MLB adopted the rule this season and there has been a notable increase in stolen bases so far. In the first three weeks of the 2023 season, USA Today reported stolen bases were up 40 percent from the previous nine seasons. 

4. Ban The Shift

One of the things that saved baseball in the late 1990s was the (enhanced) offensive, power-hitting explosion of the 1998 season. 

Fans love it when teams score runs. 

But over the last decade-plus, the ".300 average hitter" became increasingly rare, power hitters routinely hit well below .250 and the concept of a "true two-outcome hitter" became prominent: The batter was either going to hit a home run or get an out. 


The shift. The bane of many baseball fans, and bunt enthusiasts, existence. 

The shift became a problem for baseball as teams began putting the entire defensive infield on one-side. Third basemen would play as a fourth outfielder– in right field. If fans weren’t clamoring for their lefty-power hitter, like Bryce Harper, to lay down the bunt since there were literally no infielders on the left side of the field, they were frustrated that even hard-hit balls would be swallowed by a field. 

What was a hit in 1985 was a ground-out in 2022. 

Now, some baseball observers would say the hitters needed to get better at hitting opposite field hits, but the problem still existed: teams were getting on base less. Other fans disliked the shift because it skewed how traditional baseball was played.

Well, not anymore. The Atlantic League banned the shift in 2019 and in 2023 MLB did the same. 

5. The Ghost Runner, Or The Non-Scary Term: The Extra-Inning Free Runner

In December 2018, the Atlantic League implemented an extra-innings rule where a player would start the inning on second base. The rule came a few months after an epic 18-inning World Series game between the Red Sox and Dodgers. 

When the COVID-19 Pandemic caused a shortened 2020 season, one of the rules put in place by MLB was the same “Free Runner” or “Ghost Runner” rule from the Atlantic League. 

This was supposed to limit marathon extra inning games. While the rule doesn’t include postseason games, it’s one of the few pandemic-era baseball rules to survive. MLB officially adopted the rule in 2021 and it is still in place. 

Did the Atlantic League Successfully Test Robot Umps For MLB?

Yes. "Robo Umps" passed their Atlantic League test and advanced to the minors. 

MLB umpires have never been more dissected than today with the use of advanced statistics, camera angles and social media. The human error and questionable judgment of a living, breathing person was just too frustrating for some fans. 

Enter the machines. 

In 2019, the Atlantic League used “TrackMan” a radar system that helped track where the ball landed inside or outside the zone. The Atlantic League used the system up until 2022, when MLB decided to move "Automated Ball-Strike" to the minors.

From the Atlantic League: 

The Atlantic League has used the Automated Ball-Strike (ABS) system since the second half of its 2019 season and throughout the 2021 campaign as part of its innovative Test Rules and Equipment Partnership with Major League Baseball (MLB). Following the ALPB experiment and assessment, ABS is moving to an MLB affiliated league.

The Atlantic League is no longer using ABS.

What Atlantic League Rules Did MLB Not Implement?

1. Mound Visit Rules

In 2019, MLB limited mound visits to five per game effective in 2020. Prior to 2019, MLB allowed only six mound visits. “MVR” or “Mound Visits Remaining” became a phrase in MLB.

In 2019, the Atlantic League banned mound visits that didn’t include a pitching change. 

2. Mound Distance

Most rules seem cosmetic at their core. Pitch clocks to speed the game up. Shift banning because some felt it should have been illegal in the first place. But moving the pitching mound may have been one of the biggest possible baseball changes out of the bunch. 

In 2019, the Atlantic League moved the mound back by two feet (62 feet, 6 inches) from homeplate. The move was supposed to aid hitters by cutting down strike outs. 

MLB did not make this move and the Atlantic League scrapped it 2022. The Atlantic League said the results of the mound changes were "inconclusive."

"Atlantic League pitching rubber distances were moved back one foot to 61’6” for the second half of the 2021 season as part of the MLB test rules partnership. The test proved inconclusive, so both parties agreed to restore the pitching rubber distance to its traditional length of 60’6” for the upcoming ALPB season."

The Pinch Runner? The Double Hook? Here’s What the 2023 Atlantic League Is Testing For MLB

Nothing is over until it’s over when it comes to testing rules that could improve baseball play, and that means the Atlantic League is still trying some things in 2023. 

In April, the Atlantic League announced they would be using a “Designated Pinch Runner.”  

It's what it sounds like. 

Much like the Designated Hitter, a Designated Pinch Runner would enter for a hitter, run the bases but that player he was subbed in for would be allowed to re-enter the game. 

The double-hook was used in the Atlantic League in 2022, and the league will continue to use it this season. The rule may be more realistic for MLB to adopt than the pinch runner. 

According to the Associated Press: 

“The double-hook" designated hitter rule allows teams to use the DH throughout the game as long as the starting pitcher throws at least five innings. If that doesn't occur, then the team loses its DH and the pitcher's spot would bat for the remainder of the game. The rule was also used in the Atlantic League last season.”

The Atlantic League is also further testing “disengagement rules.” This limits the amount of times a pitcher can attempt a pickoff. MLB implemented several disengagement rules in 2023 that have, combined with the wide bases, led to an increase in stolen bases. 

Where Can I Watch These Experimental Baseball Rules In The Atlantic League?

FloBaseball and the FloSports App are the official streaming partner of the Atlantic League. Watch all this season's action on FloBaseball or the FloSports App, including replays of games and highlights. 

For a limited time, all Atlantic League teams will offer season ticket holders a 25 percent discount on monthly or annual FloSports subscriptions. Each club will contact their season ticket holders with details.

About the Atlantic League of Professional Baseball (ALPB)

Celebrating its 25th Anniversary season in 2023, the Atlantic League is Major League Baseball’s first Professional Partner League, a player gateway to the major leagues, and a leader in baseball innovation. ALPB has sent over 1,200 players to MLB organizations while drawing more than 45 million fans to its family-friendly ballparks throughout its 25-year history. Please visit