PHOENIX -- Thirteen spring stadiums and over 60% of Cactus and Grapefruit League games will feature an automated ball-strike (ABS) challenge system as MLB continues to inch closer to using it during the regular season -- though that won't occur any earlier than 2026.

The league is testing out the system at the big league level for the first time after years of experimenting with ABS in the minor leagues. The rules are as follows:

During the spring, each team will be given two challenges per game and will retain successful challenges.

Only the batter, catcher or pitcher can initiate a challenge, which must happen immediately after the umpire's call. The player must quickly tap his hat or helmet to indicate a challenge.

The results of the challenge will be displayed on the scoreboard and television broadcast to communicate whether a call was overturned or not.

The five dual-team stadiums in Arizona -- Seattle Mariners/San Diego Padres, Chicago White Sox/Los Angeles Dodgers, Kansas City Royals/Texas Rangers, Cincinnati Reds/Cleveland Guardians and Colorado Rockies/Arizona Diamondbacks -- will all have the system in use this spring.

The same is true for the eight teams that play in Florida -- Toronto Blue Jays, Detroit Tigers, New York Yankees, Pittsburgh Pirates, Philadelphia Phillies, New York Mets and St. Louis Cardinals/Miami Marlins.

Every game in each of the above stadiums will employ the challenge system. The league plans to gather data throughout the spring in hopes of determining whether the system is ready to bring to the major league level a year from now.

Additionally, Triple-A baseball will employ the challenge system during the 2025 regular season, giving the league as much information as possible before a decision is made on 2026.

League officials are encouraging players to use the system liberally throughout spring training. After years of experimenting with ABS in the minors, the league determined that both players and fans prefer a challenge system to having every pitch call be automated.

The league believes a challenge system would be less disruptive while retaining the human elements of the game, including pitch framing by catchers.

The league says a challenge takes about 17 seconds to complete. Experiments in the minor leagues showed an overturn rate of about 50%. On average, there were 3.9 challenges per game during minor league testing.

After collecting data, including talking to players, coaches and umpires throughout the spring, and evaluating the Triple-A regular season, the league's competition committee will determine if ABS becomes a reality in Major League Baseball's regular season and postseason.

The first game to feature the challenge system will be between the Dodgers and Cubs on Thursday at Camelback Ranch in Glendale, Arizona.