Korean baseball league introduces automated ball-strike system for 2024 as MLB mulls future with robot umps

The Korea Baseball Organization will introduce the automated ball-strike system (ABS) next season, the league announced Thursday (per the Korea Times). The league will also adopt a pitch timer similar to one used by Major League Baseball. The decisions were made during a board of directors meeting earlier this week.

"The ABS system has accomplished a precision and consistency of ball-strike calls. We have also reduced the time it takes for the calls to be relayed to the umpires," the KBO said in a statement (per the Korea Times). "By introducing the ABS to the KBO, it will ensure fair play for pitchers and hitters alike."

The KBO has used the Futures League, essentially its minor league, to refine ABS since 2020, and they originally planned to adopt it in July. The system was not deemed ready, however. The KBO also studied MLB's pitch timer, which reduced the average time of game 24 minutes this season. The average KBO game was three hours and 19 minutes in 2023. 

In June, MLB commissioner Rob Manfred said ABS is not likely to used in the big leagues in 2024. The league has been testing and tweaking the system in the minors the last several seasons, including at every Triple-A ballpark in 2023. MLB introduced several rule changes this season, including the pitch timer and a ban on extreme infield shifts.

"I think there's some sentiment among the group that we made had a lot of changes here," Manfred told the Associated Press in June. "We ought to let the dust settle and there are clearly unresolved operational issues with respect to ABS. Despite all the testing, we still have some things that are unresolved."

MLB tests two version of ABS in Triple-A this year. A fully automated zone was used Tuesday, Wednesday, and Thursday, then a challenge system was used Friday, Saturday, and Sunday (Monday is an off-day in the minors). With the challenge system, a human umpire called balls and strikes, and each team can appeal three calls to ABS per game. 

The challenge system was used during the annual Futures Game in July. Here it is in action:

According to The Athletic, MLB made adjustments to ABS that created a more personalized strike zone for each hitter last month. Throughout the season several Triple-A pitchers said the ABS zone is tight, particularly on the corners. For what it's worth, offense increased significantly in Triple-A this year, and it's reasonable to assume ABS played at least some role in the spike.

Tighter corners led to more walks and also more slug, because pitchers had to come over the plate more often. More offense is not necessarily a bad thing, though ABS would be a seismic change to the sport. MLB wants to make sure they have the best and most accurate version of ABS before bringing it to the big leagues.

MLB is expected to continue testing ABS in the minors in 2024, and possible expanding its used to other levels.