Last week, Major League Baseball and the Atlantic League announced two news test rules that would be implemented during the 2021 Atlantic League season.

The independent Atlantic League of Professional Baseball will experiment with two revolutionary rule changes in the 2021 season, limiting teams’ use of the designated-hitter position to when their starting pitcher is in the game and lengthening the distance between home plate and the pitcher’s rubber by one foot. 

These changes have been implemented by Major League Baseball as part of an ongoing partnership between the two leagues that began in 2019 to examine the effects of various rule and equipment alterations. Coupled with the rule changes that will be tested at the affiliated Minor League levels in 2021, they will provide data and discussion for potential future use in MLB. 

“The Atlantic League is an important step in the pipeline for potential rule changes at the Major League level,” said MLB executive vice president of baseball operations Morgan Sword, “and we look forward to seeing them brought to life in a competitive environment.” 

The DH rule, to be known as the “Double-Hook” rule (because the DH is removed from the game at the same time as the starting pitcher), will be in effect the entirety of the 2021 season, while the change to the mound distance will be made in the second half. 

The Atlantic League will also continue to use the automatic ball-strike system — the so-called “robot ump” that assists the home-plate umpire in judging the strike zone. That system will also be in effect in the affiliated Low-A Southeast League this 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. “The ALPB is a forward-thinking league, and it is satisfying to our teams and players to be leaders determining the future of our sport.” 

Previous Atlantic League experiments include the three-batter minimum (which has since become a Major League rule), restrictions on defensive positioning (which will be used in Double-A this year) and 18-inch square bases (which will be used in Triple-A this year). 

With the next collective bargaining agreement talks looming, MLB felt it important to utilize 2021 for a variety of rule experiments. It is safe to assume, however, that neither of these Atlantic League rules would jump straight from indy ball to the big leagues. If they are deemed worthy of future use, they would be further tested in the Minors first.

 “Fans, players and many others in the baseball community have expressed an interest in seeing more regular action on the field,” said MLB rules consultant Theo Epstein, former GM of the Cubs and Red Sox. “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. We are grateful that the Atlantic League — which has been at the forefront of successful rule experiments in the past — has agreed to test a 12-inch increase in the distance between the pitching rubber and home plate during the second half of the season. We expect to learn a great deal about the impacts of such a change and whether an adjustment to this critical field dimension is worth potential future consideration at other levels of professional baseball.”

 The Atlantic League features eight teams playing between 118 and 120 games apiece from May 27 through Oct. 10. 

Here is a more in-depth look at the two Atlantic League changes for 2021 and what MLB hopes they can accomplish:

 THE “DOUBLE-HOOK” DH RULE 

The baseball world has typically been divided between DH devotees and those who prefer the old-school National League rules that — aside from the temporary use of the universal DH as part of coronavirus-related health and safety protocols in 2020 — require pitchers to hit. This “Double-Hook” rule would be a compromise, of sorts. It utilizes the DH spot that has been in effect in the American League since 1973. But once a team’s starting pitcher is replaced, the pitching spot takes over the DH spot in the batting order. So from that point on, the team would be required to either use a pinch-hitter in that spot or let the relief pitcher bat. 

The impetus behind this idea is to incentivize teams to push their starters deeper into games. Nearly 90% of pitching starts in the 2020 MLB season lasted less than seven innings. The increasingly early use of relievers — including the use of the “opener” strategy — diminishes the role of the starter. Yet there is widespread agreement that having identifiable starters — workhorses around whom fans schedule their viewership or attendance — is good for the sport. In preventing starting pitchers from batting, unnecessary injuries, such as the forearm fracture D-backs ace Zac Gallen suffered while taking batting practice this spring, would be avoided.

And the combination of expanding the DH to another league and compelling clubs to use their starters longer in games would conceivably improve offensive performance across the board. Plus, lovers of the NL rules would still get the late-inning managerial strategy they desire. So the “Double-Hook” takes the best of both leagues and blends it all together. 

MOVING THE PITCHING RUBBER (SECOND HALF ONLY)

 Baseball’s dedicated distance from the rubber to the rear of home plate has been 60 feet, 6 inches since 1893. So the new Atlantic League distance of 61 feet, 6 inches will be considered by some to be an audacious expansion — one small step for pitchers, one giant leap for baseball itself. But several factors contribute to the idea of adjusting that seemingly sacred space between pitcher and batter.

 First and foremost, Major League strikeout rates have risen every season since 2005 (the league-wide K rate was 16.4% in ’05 and was 24.9% through Monday’s play). Having roughly one-quarter of all plate appearances end in a strikeout is generally agreed to be detrimental to the game’s entertainment value. The strikeouts increase is in part due to a dramatic increase in velocity (the average four-seam fastball speed thus far in 2021 is 93.6 mph, versus a 91.9 mph average in 2008).

Additionally, research by The Ringer found that modern MLB pitchers, weighted by workload, are more than four inches taller, on average, than they were when the 60’6” distance was implemented in 1893. All of which is to say that professional baseball may have arguably outgrown 60’6”. Moving the pitching rubber back a foot will provide batters with more time to react to pitches, potentially improving contact rates and thereby injecting more action into the game.

MLB found that the reaction time on a 93.3 mph fastball (the average four-seam velocity in 2020) thrown from 61’6” is equivalent to a 91.6 mph fastball (about the average fastball velo in 2011) thrown from 60’6”. MLB also determined that a 12-inch increase would be the minimum interval needed to evaluate a change in mound distance. While a larger increase in the distance was considered, the goal is to make a change without disruption or added injury risk. 

The American Sports Medicine Institute conducted a study in 2019 that found that collegiate players throwing from distances of 60’6”, 62’6” and 63’8” demonstrated no significant differences in key measures of rotational motion or acceleration. Velocity and strike percentage remained consistent, as well.

As part of the mound change experiment, the TrackMan technologies installed in Atlantic League parks will be upgraded to project and measure pitches and evaluate outcomes. 

A 12-inch increase in the distance might not be as drastic as it sounds. As part of its analysis, MLB found the standard deviation in how catchers set up behind the plate to be seven inches. Some catchers set up as much as three feet further back from the plate than their peers. The 60’6” standard, therefore, is not as standard as we assume. 

Why will the mound distance only be moved for the second half of the Atlantic League season? Because doing so will provide a control group. The first-half data will be compared with the second-half data to determine the true effects of the change. It is worth noting that when 60’6” became the National League standard in 1893 — a full five feet farther than the mound had sat the year prior — the league-wide strikeout rate declined from 8.5% to 5.2% and batting average increased from .245 to .280. MLB also lowered the height of the mound from 15” to 10” in 1969, helping to lower the strikeout rate from 15.8% to 15.2% and raise batting average from .237 to .248. Mound modifications aimed at improving offensive performance, therefore, are not without precedent.

Click HERE to watch Theo Epstein’s explanation of the new rules on the Atlantic League’s official website.

Today, the Atlantic League confirmed the return of MLB test rules from the 2019 season.

(April 22, 2021, New York) – Following its joint announcement last week with Major League Baseball regarding 2021 test rules, the Atlantic League of Professional Baseball (ALPB) today announced rules it will retain from the MLB experiments conducted in 2019. Many of these changes debuted in the Atlantic League that season and have been adopted by MLB for use in affiliated minor leagues.

“We’ve always known that MLB tests have the potential to land in the Majors,” said Atlantic League President Rick White. “MLB’s recent announcement that several of the 2019 experimental rules will be tested this season in affiliated minor leagues is another indicator that these may be the future of our game. It’s our goal to make our players ready for that future, so we are happy to continue many of these rules and provide more performance data to our partners at Major League Baseball.”

The most conspicuous of the returning rules is the Automated Ball-Strike System (ABS), which first made headlines at the Atlantic League All-Star Game in York, PA, in 2019. Now commonly known as “robo-umps,” the system uses newest generation Trackman tracking software to instantly relay a call of “ball” or “strike” to the earpiece of the home plate umpire. MLB announced it will expand use of the ABS to its Low-A Southeast league this season.

The three-batter minimum rule requiring pitchers to face at least three batters or reach the end of an inning before exiting the game was instituted in Major League Baseball last year and is in effect this season as well. It will again be in place when the Atlantic League begins play on May 27.

The Atlantic League will continue to use 18-inch bases. Three inches larger than traditional bags, the larger bases will also be used on AAA affiliated diamonds this year.

Atlantic League infielders will again be required to be on the infield dirt when a pitch is released this year. MLB will further test that rule at the AA level in 2021.

The time between innings will continue to be limited to one minute, 45 seconds, down from the previous two minutes, five seconds and in keeping, White said, with the ALPB’s longstanding efforts to improve the pace of play of the game.

Four other returning rules continue that effort. The extra inning tie-breaker, implemented in the Atlantic League before its rules test initiative with MLB, will continue. The rule places a runner at second base in the first extra inning of a regular season game. This rule was implemented in the big leagues in 2020 and is in effect this MLB season.

Managers, coaches, and players will be limited to three “timeouts” each nine-inning game, one timeout in the 10^th inning, and one time out every three innings thereafter, reprising a rule originally introduced in the ALPB.

The league retains the intentional base on balls rule it implemented several years prior to MLB implementation in 2019.

Atlantic League pitchers will be limited to a 15-second period between pitches, which MLB will test in the Low-A West. 

About the Atlantic League of Professional Baseball (ALPB)

The Atlantic League is the first Professional Partner League of Major League Baseball, a player gateway to the major leagues, and a leader in baseball innovation. ALPB has sent over 950 players to MLB organizations while drawing over 42 million fans to its family friendly ballparks throughout its 24-year history. Please visit www.AtlanticLeague.com.