Size Matters: MLB Announces Experimental Playing Rules To Be Tested During 2021 Minor League Season; Triple-A To Increase Base Size
New York, NY (March 11, 2021) - Major League Baseball (MLB) announced today the testing of a variety of experimental playing rules at various levels of the Minor Leagues during the upcoming 2021 season. These experimental playing rules have been approved by the Competition Committee and the Playing Rules Committee.
New York, NY (March 11, 2021) - Major League Baseball (MLB) announced today the testing of a variety of experimental playing rules at various levels of the Minor Leagues during the upcoming 2021 season. These experimental playing rules have been approved by the Competition Committee and the Playing Rules Committee. MLB will closely monitor and analyze the impact of each rule change throughout the 2021 season and report to Clubs on their effects for further analysis. Consistent with the preferences of our fans, the rule changes being tested are designed to increase action on the basepaths, create more balls in play, improve the pace and length of games, and reduce player injuries.
Below is a summary of the experimental rules that will be tested during the 2021 Minor League season, which will vary by level of play:
TRIPLE-A (LARGER BASES): To reduce player injuries and collisions, the size of first, second and third base will be increased from 15 inches square to 18 inches square. The Competition Committee also expects the shorter distances between bases created by increased size to have a modest impact on the success rate of stolen base attempts and the frequency with which a batter-runner reaches base on groundballs and bunt attempts.
DOUBLE-A (DEFENSIVE POSITIONING): The defensive team must have a minimum of four players on the infield, each of whom must have both feet completely in front of the outer boundary of the infield dirt. Depending on the preliminary results of this experimental rule change, MLB may require two infielders to be positioned entirely on each side of second base in the second half of the Double-A season. These restrictions on defensive positioning are intended to increase the batting average on balls in play.
HIGH-A (“STEP OFF” RULE): Pitchers are required to disengage the rubber prior to throwing to any base, with the penalty of a balk in the event the pitcher fails to comply. MLB implemented a similar rule in the second half of the Atlantic League season in 2019, which resulted in a significant increase in stolen base attempts and an improved success rate after adoption of the rule.
LOW-A (PICKOFF LIMITATION, PITCH TIMER, AND ABS):
o ALL LOW-A LEAGUES: Pitchers will be limited to a total of two “step offs” or “pickoffs” per plate appearance while there is at least one runner on base. A pitcher may attempt a third step off or pickoff in the same plate appearance; however, if the runner safely returns to the occupied base, the result is a balk. Depending on the preliminary results of this experimental rule change, MLB will consider reducing the limitation to a single “step off” or “pickoff” per plate appearance with at least one runner on base.
o LOW-A SOUTHEAST: In addition to the limitations on step offs/pickoffs, MLB will expand testing of the Automatic Ball-Strike System (“ABS”) that began in the Atlantic League and Arizona Fall League to select Low-A Southeast games to assist home plate umpires with calling balls and strikes, ensure a consistent strike zone is called, and determine the optimal strike zone for the system.
o LOW-A WEST: In addition to the limitations on step offs/pickoffs, following successful pace of game rules testing among Florida State League teams in 2019, on-field timers (one in the outfield, two behind home plate between the dugouts) will be implemented to enforce time limits between delivery of pitches, inning breaks and pitching changes. The on-field timer used in Low-A West will include new regulations beyond the system currently used in Triple-A and Double-A to reduce game length and improve the pace of play.
“We are listening to our fans. This effort is an important step towards bringing to life rules changes aimed at creating more action and improving the pace of play,” said Michael Hill, MLB Senior Vice President of On-Field Operations. “These experimental playing rules have been approved by the Competition Committee and the Playing Rules Committee to be tested and analyzed in a highly competitive environment.”
“These experimental rules are designed to put more balls in play, create more excitement on the basepaths and increase the impact of speed and athleticism on the field,” said Raúl Ibañez, MLB Senior Vice President of On-Field Operations. “As another important goal of the rules approved by the Competition Committee and the Playing Rules Committee, we expect the new larger bases to increase player safety. We look forward to testing these rules in the Minor Leagues.”
“The game on the field is constantly evolving, and MLB must be thoughtful and intentional about progressing toward the very best version of baseball – a version that is true to its essence and has enough consistent action and athleticism on display to entertain fans of all ages,” said Theo Epstein, Consultant to MLB. “These rules experiments will provide valuable insight into various ways to create a playing environment that encourages the most entertaining version of the game. What we learn in the Minor Leagues this year will be essential in helping all parties chart the right path forward for baseball.”
MLB also continues its three-year partnership agreement with the Atlantic League of Professional Baseball (ALPB), which was announced in 2019. This partnership agreement allows MLB to test and adjust experimental playing rules and changes to equipment each season. Any new experimental playing rules for the 2021 season will be announced in the coming weeks.
# # #
Contact: Matt Bourne or Michael Teevan, MLB Communications, (212) 931-7878, mlbpressbox.com, @MLB_PR.
MiLB podcast discusses Anthony, Caglianone at Triple-A
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
These are the greatest Minor League promos happening in June
Benjamin Hill travels the nation collecting stories about what makes Minor League Baseball unique. This excerpt from the Baseball Traveler newsletter, presented by Circle K, is a mere taste of the smorgasbord of delights he offers every week. Read the full newsletter here, and subscribe to his newsletter here.
New playoff format coming to 2025 Dominican Summer League
Minor League Baseball announced the 2025 Dominican Summer League (DSL) season will begin June 2 with Opening Day festivities taking place at the Boston Red Sox Academy in Guerra. The 2025 campaign will also see the introduction of the DSL Cup, a new playoff format that will see 16 DSL
Debating best Minor League home caps on podcast
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
The Omaha Storm Chasers' 'Take Meow-t' cat night included a Litter Box Sundae
Benjamin Hill travels the nation collecting stories about what makes Minor League Baseball unique. This excerpt from the Baseball Traveler newsletter, presented by Circle K, is a mere taste of the smorgasbord of delights he offers every week. Read the full newsletter here, and subscribe to his newsletter here.
Boston's Triple-A affiliate throws birthday bash for Roman Anthony
With all the hype that has surrounded Roman Anthony over the past two seasons, it’s easy to forget how young he really is. MLB's No. 1 prospect played 70 games at the highest level of the Minors before he could order a beer. But he can now. Roman Anthony turned
Friendly foes, 2024 first-rounders Moore and Caglianone trade first Triple-A homers
For years, Christian Moore and Jac Caglianone laced up their cleats against one another in the SEC. A rivalry that spanned Florida, Tennessee and other landmarks across the South moved to Salt Lake City this week as the Royals and Angels' top prospects got simultaneous Triple-A promotions. So it was
Phillies' Moore, Fausnaught join MiLB podcast
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
Red Sox prospect rips double THROUGH Fenway-esque scoreboard
Red Sox No. 4 prospect Franklin Arias, an infielder for High-A Greenville, REALLY didn’t want to let visiting Asheville score any runs in the top of the eighth inning on Friday night. With runners on first and second base in the bottom of the fourth, Arias showed he apparently held
April's hottest hitting prospects -- one for each organization
The Minor League season is a month old and several of the game's best hitting prospects are off to fast starts. Red Sox outfielder Roman Anthony is tearing up Triple-A (just like he did at the end of last year), Padres shortstop Leo De Vries is leading the High-A Midwest
Check out the best -- and wackiest -- Minor League promos happening in May
Benjamin Hill travels the nation collecting stories about what makes Minor League Baseball unique. This excerpt from the Baseball Traveler newsletter, presented by Circle K, is a mere taste of the smorgasbord of delights he offers every week. Read the full newsletter here, and subscribe to his newsletter here.
Orioles' Honeycutt joins The Show Before the Show
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
MiLB podcast coming LIVE to a Somerset this June
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
New ballparks highlight 2025 MiLB road trip stops
Benjamin Hill travels the nation collecting stories about what makes Minor League Baseball unique. This excerpt from the Baseball Traveler newsletter, presented by Circle K, is a mere taste of the smorgasbord of delights he offers every week. Read the full newsletter here, and subscribe to his newsletter here.
Minor League Baseball partners with TruGreen
FRANKLIN, Tenn. -- TruGreen, the nation's leading lawn care treatment provider, is proud to announce a groundbreaking partnership with Minor League Baseball that includes activations across all 120 clubs, a makeover of the home dugout in each market, sponsorship of select MiLB team grounds crews, and a new initiative called
Podcast explains why the Syracuse Mets are looking for Jim Morrison
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
Dash im-prom-tu promo and Mets' Suero joins the podcast
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
Minor League Baseball partners with Circle K
Minor League Baseball announced a new national partnership with Circle K, which will see the convenience store giant become the “Official Convenience Store of Minor League Baseball.” During the 2025 season, the Circle K brand will be integrated into the MiLB in-stadium experience through in-game video board assets at most
These 15 moments led to season No. 15 of Minor League road trips
Benjamin Hill travels the nation collecting stories about what makes Minor League Baseball unique. This excerpt from his newsletter is a mere taste of the smorgasbord of delights he offers every week. Read the full newsletter here, and subscribe to his newsletter here.
MiLB podcast crew makes Opening Day predictions
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
Everything you need to know for Triple-A Opening Day
First, there was big league Opening Day. Now it's Triple-A's turn to take the spotlight. The Minor League season opens Friday when the Triple-A International League and Pacific Coast League seasons get underway for the first of MiLB’s two Opening Days. And right out of the gates, several of baseball's
Top prospects to watch at Triple-A -- one for each organization
It’s Triple-A’s turn up to bat on Friday. The regular season begins for the Minor Leagues’ highest level one day after the action starts on the Major League side. Fun fact: it’ll be the earliest start to a Minor League season since 1951 (March 27). Double-A, High-A and Single-A will
Here's where every Top 100 prospect is expected to start the season
The 2025 Opening Day prospect roster announcements began last week when the Cubs informed Matt Shaw (MLB No. 19) he was making the trip overseas to compete in the Tokyo Series. Roki Sasaki (No. 1) also received the good news, but his assignment was much less of a surprise. Now
Nationals prospect King joins MiLB podcast
Check out the latest episodes of The Show Before the Show, MiLB.com's official podcast. A segment rundown is listed below, in case you want to skip to a particular section. Like the podcast? Subscribe, rate and review on Apple Podcasts. The podcast is also available via Spotify, Megaphone and other
Here are the 2025 All-Spring Breakout Teams
Fifteen games, several jersey swaps and countless highlights later, the second edition of Spring Breakout has officially concluded – and it lived up to its billing. Of the 16 contests sprinkled across four days, only one game (Dodgers vs. Cubs) was rained out. Coincidentally, the Cubs were one of two