MLB To Test Checked-Swing Challenges In The Florida State League

Image credit: (Photo by Bill Mitchell)

Beginning Tuesday, Major League Baseball will begin experimenting with using technology to rule on checked-swing challenges in the Low-A Florida State League.

News of the rollout to the FSL was first reported by the Wall Street Journal and has been confirmed by Baseball America.

The checked-swing challenge system will echo what was experimented with in the Arizona Fall League last October, as it will use the same 45-degree angle implemented in the AFL. The idea is that the barrel must cross a 45-degree line that matches the angles of the the first and third base foul lines.

There is no actual clear-cut definition of what a checked swing is in the MLB rule book. Most modern fans may think of the bat head crossing a parallel line that mirrors the front of home plate, but that is merely an interpretation. Previously, checked swings were determined by whether the hitter’s “wrists broke”, and checked-swing rules in the 1950s and 60s were much more generous to the hitter.

The 45-degree rule, in which a batter’s barrel must go well beyond parallel with the plate, is designed by MLB to give batters a bit more leeway in a baseball environment that’s seen strikeouts rise decade by decade.

Teams will be allowed one unsuccessful challenge a game. Successful challenges do not count against the quota, so if you keep challenging successfully, you can keep challenging. Much like the Automated Ball Strike (ABS) challenge system for ball and strike calls, a challenge must be made almost immediately. Then the results will be displayed on the video board for all in the stadium to see.

MLB has historically liked to use the Florida State League as a place to trial experimental rules. It was the first MiLB league to use the ABS system, and it has also been used for shift rule trials.