Atlantic League, in partnership with MLB, to try more experimental rules in 2021

Rick White

In 2021, the Atlantic League will again serve as an experimental testing ground for Major League Baseball.

As a result, York Revolution fans will get to witness some new experimental rules during the 2021 Atlantic League season that could eventually work their way into major league games.

The new rules were announced Wednesday in a joint news release from the Atlantic League and Major League Baseball. The Atlantic League is a partner league to MLB.

The Revs’ Atlantic League season starts Friday, May 28.

The first change is being labeled the “double-hook” designated-hitter rule and will be in place for the entire Atlantic League season. The second change will move the pitching rubber back one foot, to 61 feet, 6 inches, and will only be implemented for the second half of the Atlantic League season.

"We are pleased to play a critical role in Major League Baseball’s tests and evaluation of experimental rules,” Atlantic League president Rick White said in the news release. “The (Atlantic League) is a forward-thinking league, and it is satisfying to our teams and players to be leaders determining the future of our sport.”

In 2019, the Atlantic League also implemented several other experimental rules that were later adopted for use in the affiliated minor leagues or in the major leagues. The 2020 Atlantic League season was canceled because of the COVID-19 pandemic, preventing any experimentation during that season.

The DH change: For 2021, the DH change states that once a team’s starting pitcher is replaced, the team will lose its DH for the remainder of the game. The club will be required to use a pinch hitter, or the relief pitcher will bat.

The “double-hook” rule represents a potential compromise between the historical rules of the National League (which has not employed the DH, except in the COVID-shortened 2020 season) and the American League (which has used the DH since 1973).

Additionally, the new rule could incentivize teams to leave their starting pitchers in longer, increasing the value of starters who can work deeper into games. Nearly 90% of pitching starts in the major leagues in 2020 lasted fewer than seven innings.

The change could also increase the strategic element in the late innings of a game.  

Moving back the rubber: The decision to move back the pitching rubber should provide batters with more time to react to pitches.

The expectation is that more reaction time will help batters make more frequent contact, putting more balls into play and creating more action in the game.

According to the news release, the reaction time on a 93.3 mph fastball (the average MLB velocity in 2020) thrown from 61-6 is approximately equivalent to a 91.6 mph fastball (the average fastball velocity in 2010) thrown from 60-6.

Strikeouts on the rise: As pitchers have gained velocity and used technology to improve the effectiveness of their pitches, the strikeout rate in MLB has increased for 15 consecutive years, from 16.4% of plate appearances in 2005 to an all-time MLB record 23.4% in 2020.

An analysis performed by MLB determined that a 12-inch increase would be the minimum interval needed to evaluate a change in mound distance. It’s hoped that the change will be meaningful without being disruptive.

Theo Epstein

“Fans, players and many others in the baseball community have expressed an interest in seeing more regular action on the field,” MLB consultant Theo Epstein said in the news release. “Therefore, it’s important that we use the 2021 season to explore various ways to create more frequent contact — and the increased action and athleticism on display that will follow.”

Epstein formerly led the baseball operations for the Boston Red Sox and Chicago Cubs.

Safety concerns: The news release stated that the change was also determined to be safe, since it does not require the pitcher to alter pitching mechanics and there is no evidence of increased injury risk.

The American Sports Medicine Institute conducted a study in October of 2019 that measured the impact of pitching distance on biomechanics. In the study, high-level collegiate baseball players threw from distances of 60-6, 62-6 and 63-8. No significant differences in key measures of rotational motion (kinetics) or acceleration (kinematics) were observed among the varying pitching distances. In addition, ball velocity and strike percentage remained consistent.

It was also announced that MLB and the Atlantic League are partnering to upgrade the TrackMan tracking technology that will be used during the 2021 season to project and measure pitches.

Precedent for change: There is precedent for pitching changes.

In 1893, the National League moved back the pitching rubber 5 feet, to its current distance of 60-6. The result was that the strikeout rate declined from 8.5% in 1892 to 5.2% in 1893, and batting average increased by 35 points (rising from .245 in 1892 to .280 in 1893).

In 1969, in addition to reducing the size of the strike zone and prohibiting the use of foreign substances, MLB lowered the height of the mound from 15 feet to 10 feet. The result was that the strikeout rate fell 4% (decreasing from 15.8% in 1968 to 15.2% in 1969) and batting average rose by 11 points (increasing from .237 in 1968 to .248 in 1969).

Atlantic League umpire Brian deBrauwere wears an earbud during a demonstration of the automated ball-strike system at PeopleBank Stadium Monday, July 8, 2019.

Continued use of ABS: In addition, the Atlantic League will continue its use of the Automated Ball-Strike System (known by many as the robot umpire) to assist the home-plate umpire in calling balls and strikes.

In 2021, ABS in the Atlantic League will feature upgraded ball-tracking technology and modifications to the geometry of the strike zone in order to better match the strike zone that players are familiar with and encourage more action in the game. The system was first used in the Atlantic League in 2019.

MLB will analyze the effects of these changes before deciding on potential additional modifications during the midpoint of the 2021 Atlantic League season and in future seasons.

The experimental playing rule changes are part of a three-year agreement between MLB and the Atlantic League that was announced before the 2019 season.

Experimental rules that have been adopted: A number of experimental rules that were first implemented in the Atlantic League in 2019 have been adopted in the minor leagues or the major leagues. 

Examples include the three-batter minimum, which requires the pitcher to face a minimum of three batters or complete an inning before being removed from the game. That became a major league rule in 2020.

In addition, ABS, which uses pitch tracking technology to call balls and strikes, will be used in a Low-A league in 2021, the step-off rule will be used in High-A, restrictions on defensive positioning will be used in Double-A and 18-inch bases will be used in Triple-A. Each of those rules were first tested in Atlantic League play during the 2019 season.

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