On Wednesday, December 4, the Korea Baseball Organization (KBO) announced some changes to their rules ahead of the 2025 season. Two rule changes will be going into effect, one focusing on the pitch clock and the automated ball-strike (ABS) system.
MLB introduced the pitch clock in 2023, and after the rule was proposed to be in the KBO in 2024, the pitch clock will debut in the KBO this upcoming year. There are slight differences from MLB’s pitch clock, where pitchers must start their delivery within 20 seconds with bases empty and 25 seconds with runners on base. MLB gives pitchers 15 seconds with no runners on and 18 seconds with runners on base. One interesting stat in 2024 was that the KBO kept track of pitch clock violations, but no penalties were distributed.
Also, beginning in 2025, there will be a 33-second limit between trips to the plate for batters, who only get two timeouts per plate appearance. Also, there will be no limit on the number of disengagements for pitchers, departures from MLB, where pitchers could step off the rubber or make a pickoff attempt only twice per at-bat to rest the pitch clock.
The ABS strike zone was implemented for 2024 but will be readjusted in 2025. For 2024, the top of the ABS strike zone was set at 56.35 percent of a batter’s height, with the bottom at 27.64 percent. Slight adjustments in 2024 will see those numbers change to 55.75 percent of a batter’s height and 27.04 percent at the bottom. This means that the zone will be lowered slightly, but there will be no changes to the size of the zone.
One rule that has been tested throughout the minor leagues, the Arizona Fall League and the KBO Futures Leagues, is a check swing challenge system. It could be a possibility that the KBO could adopt that rule for the 2026 season.
All of these proposed rules will be finalized following a meeting of the KBO League’s rules committee in the near future.
