Major League Baseball has done a lot of experimenting with rules, first testing the new rules in the minor leagues, and will continue this trend during the 2021 season.
The Triple-A, Double-A and High-A levels will each adopt a different change when they begin their seasons in May. The Low-A level will try out multiple ideas, according to a Thursday MLB press release.
The league said 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.
The summary the MLB released Thursday of the experimental rules that will be tested during the 2021 Minor League season vary by level of play:
Triple-A — Larger Bases: The league said 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,” a release states.
Double-A — Defensive Positioning: The MLB’s new rules say 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,” the release reads. “These restrictions on defensive positioning are intended to increase the batting average on balls in play.”
High-A — “Step Off” Rule: At the High-A level, pitchers will be 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,” the league said.
Low-A, all leagues — Pickoff Limitation: At all Low-A levels in all 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, the release states.
“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,” the release states.
Low-A Southeast — Robot strike zone: 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, the release states.
Low-A West — Pitch timers: 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,” the release reads.
MLB said it will closely monitor and analyze the impact of each rule change throughout the 2021 season and report their effects to clubs for further analysis.