MLB testing potential rule change in Fall League. What one KC Royals prospect thinks

Major League Baseball is testing a potential new addition to its replay review. In the Arizona Fall League, teams can now challenge check swings during a game.

The Check Swing Challenge system allows for umpires to take a closer look at a half-swing to determine whether it crossed home plate. The new system utilizes the “Hawk-Eye technology” to provide an accurate review of the half-swing in question.

And it’s already leaving quite the impression.

“I think it’s really cool and definitely one of those things that is super new and they are trying to incorporate it,” Kansas City Royals prospect Carter Jensen said.

The check swing reviews are only available for games at Salt River Field at Talking Stick. The venue is the spring training complex of the Colorado Rockies and Arizona Diamondbacks.

However, all six Arizona Fall League teams will have experience with the system. The Salt River Rafters currently play home games at Salt River Field.

The Surprise Saguaros, which are made up of minor-league prospects from the Royals, Cleveland Guardians, Houston Astros, Baltimore Orioles and Texas Rangers, have played multiple games at the complex.

So far, the Saguaros faced the Rafters three times at Salt River Field with the final matchup slated for Nov. 14.

Jensen, who is currently playing with the Saguaros, has noticed a few check-swing challenges during games. He felt the new system adds a unique dynamic for pitchers and catchers.

“I think it’s kind of a blessing and a curse, especially being a catcher and, you know, trying to get your pitcher out of a tough inning and they call a check swing,” Jensen said. “All of a sudden, a challenge happens and it’s overturned. But also, like as a hitter, it can be super clutch if you know you didn’t go and wanted to challenge it.”

The first check-swing review occurred on Oct. 22. Scottsdale Scorpions outfielder Drew Gilbert (New York Mets) checked his swing against the Rafters. The swing was appealed to the third base umpire and deemed a strike.

Gilbert then invoked an official challenge from home plate. He touched his helmet to designate a review of the check swing. The Hawk-Eye system came on the scoreboard and revealed that Gilbert did not swing at the pitch.

So how does the check-swing system work?

Teams have two check-swing challenges in the game. Per the new rules, only batters, pitchers and catchers can invoke an official review.

However, managers and catchers can still appeal a potential check swing to first or third base umpires as normal.

Should a team utilize both challenges before the ninth inning, the club will receive an additional challenge to use for the last frame. The official review will determine if the hitter’s bat crossed a 45-degree threshold from home plate.

Major League Baseball also continues to test the Automatic Ball-Strike (ABS) system in the Arizona Fall League. It allows for every pitch to be called either a ball or strike with automated technology.

The ABS was tested in the minor leagues this season with the same Hawk-Eye tracking. In the full system, the home plate umpire relays the automated balls and strikes to the batter, pitcher and catcher.

In Triple-A, the league implemented an ABS challenge system for balls and strikes. It’s not quite the full ABS, instead, the system is used for reviewing missed calls on pitches that seem too far outside of the strike zone.

It’s not likely the ABS will be utilized in the big leagues until at least the 2026 season. Additionally, Major League Baseball has not provided a timeline on whether the Check Swing Challenge system will be implemented.

Major League Baseball has tested several rule changes, such as the pitch clock and bigger bases, in the Arizona Fall League. Both of these improvements have reached the big-league level in recent years.

Both the ABS system and check-swing technology are still in development. Still, the new replay options are potential avenues to better enhance the game.