MLB brings never before seen swing rule experiment to Florida League in major shift

Major League Baseball is experimenting. Beginning Tuesday, the league will experiment with a new method of determining checked swings via technology. The Low-A Florida State League will see the test take place. The aim is to make checked-swing calls fairer and more accurate. The system initially was tested in the Arizona Fall League and is now set for further evaluation. If successful, MLB could implement it in higher-level games someday.


MLB tests new swing rule with technology in Florida State League


There is not an official rule in the MLB rule book that specifically declares a checked swing. Umpires used to make a call based on whether the wrist of the hitter moved or if the bat passed in front of home plate.

Those old methods are not always equitable or easy to call. Now, MLB hopes to attempt using a 45-degree angle to help make things more clear.

Unfortunately for you there’s no rule that says if his bat crosses that imaginary line that it is a swing, it is umpire discretion and they deemed that he wasn’t offering at the ball but rather attempting to move out of the way of it and turned his bat, therefore it’s a fair loss

— cdel0800 (@cdel0800) May 18, 2025

The bat needs to cross a line that is parallel to the foul lines at first and third base. If the bat does cross the line, it is a swing.

This rule allows batters more leeway, which can prevent them from being called out on pitches that are close. MLB hopes this will reduce strikeouts, which have increased in recent years.


Low-A teams led by managers like Dave Anderson will get one wrong challenge


Florida State League teams will be permitted to challenge checked-swing rulings via this new technology. One time, each team has the opportunity to be incorrect. If they challenge successfully, however, they can continue. Like with the Automated Ball Strike (ABS) system, the challenge has to occur with urgency nearly immediately following the pitch.



After the challenge is made, the outcome will appear on the video board at the stadium for all to see. This makes things more transparent and easier to comprehend. The Florida State League has been used by MLB to experiment with new rules in the past.


This league was the first to experiment with the ABS and change rules. If this checked-swing system proves effective, it may soon be implemented in other levels of the minors or potentially in the majors.


Also Read: Ethan Moore Becomes MLB Draft Prospect While Leading OPRF Baseball