Balls, Strikes, Bets, and Billions: Major League Baseball Adopts Automated Ball Strike System

Photo by Tim Gouw on Unsplash

Professional sports leagues in the United States increasingly find themselves operating in a landscape where sports betting has become mainstream. Since the Supreme Court struck down the federal prohibition on sports gambling in Murphy v. NCAA seven years ago, leagues have flipped their approach to gambling from a self-preservation-inspired avoidance of the industry to an open-armed embrace. In the context of this shift, Major League Baseball’s (MLB) decision to adopt the Automatic Ball Strike system (ABS) is more than just picking up a new technological tool to improve officiating. It is also a reflection of the league’s alignment with the unavoidable imperatives of the betting market. 

Starting in 2026, the MLB will introduce the ABS challenge system. The move follows several years of trial runs in the minor leagues, and while it falls short of eliminating the human element of umpiring behind the plate, the league hopes the change will be an acceptable middle ground. The new system works much like the current replay review system. Umpires will still make the vast majority of ball and strike calls, but a player can tap their helmet to challenge the call. Each team will begin games with two challenges and a pitcher, catcher, or batter may use them at any time during the game, so long as they do not consult with the dugout. The limitation on the number of challenges and the fact that the dugout cannot be involved in the decision adds additional layers of strategy to the new system, and will help to alleviate fan concerns that challenges will bog down the pace of play. Crucially, the ABS system is designed around a standardized, two-dimensional strike zone set in the middle of home plate, with the top and bottom of the zone calculated based on a fixed percentage of each individual player’s height. This technical definition is intended to remove the subjectivity inherent in the historical three-dimensional strike zone, ensuring greater pitch-to-pitch consistency. 

While adopting ABS will certainly improve the accuracy of calls made behind the plate, its impact extends beyond. The stated purpose of ABS is to modernize the game, to reduce controversial umpire calls, and thereby improve the product for fans, broadcasters, and sponsors. But players have noted other concerns that inspired them to support the change, primarily protecting the integrity of the game. Max Scherzer, a pitcher and member of the MLB Competition Committee, which approved the rule change, made the point that “You might want the ability to overturn an umpire's call because we can't afford to have any umpire think they can have a chance to influence a game for gambling purposes.” 

Scherzer’s concerns are not far-fetched either. Sports betting is not limited to just who wins and who loses the game; prop bets enable bettors to wager on individual aspects of each game, such as whether the first pitch to a batter will be a ball or strike, or whether a hitter will have more than a certain number of strikeouts. These prop bets are often things that umpires have significant influence over, and at the beginning of the 2025 season, the MLB fired one of their best umpires for violating the league’s sports betting policy. Additionally, two Cleveland Guardians pitchers, Emmanuel Clase and Luis Ortiz, have been federally indicted for intentionally missing the strike zone to influence prop bets. The investigation into the Guardians pitchers was kicked off when Ortiz received higher than usual betting activity on one of his starts. The betting activity that was flagged centered on microbetting, wagering on the outcome of a single pitch, such as whether it would be a ball or a hit batsman, an area of the market that is particularly susceptible to manipulation. MLB has since worked with sportsbooks to place a cap on the dollar amount that may be wagered on such props at $200. 

By making the strike zone more standardized and enabling challenges to correct the human error inherent to the game, MLB is signaling that it will provide a more consistent and predictable product. For the gambling industry, predictability and data are extremely valuable. Commissioner Rob Manfred framed the gambling issue as something the MLB never asked for, but noted that now that it is here, “you have to have a relationship with the sportsbooks. Like most relationships, if you want something from them, you need to give something back to them, and that’s where those relationships come from.” 

The exchange being made is data. Sportsbooks, like MLB’s official partner FanDuel, will gain access to the MLB’s collection of data, presumably including data from ABS. In exchange, MLB gets access to the sportsbook’s data, which can be used to track unusual betting activity, such as a uniquely large volume of bets on a player’s prop, as was the case with the two Guardians pitchers. The deal is one of necessity; gambling is not going away, so MLB needs to ensure that it does not impact the integrity of the game, and that means they need to remove the human element from officiating as much as possible. 

As legal sports gambling has penetrated its way into all of the major American sports, other leagues have made similar rule changes. Both the NBA and NFL have formed official partnerships with sportsbooks, and each has made rule changes to remove the human element from officiating in the hopes that outcomes will be more predictable and consistent. The NFL announced this season that it will be using the same Hawk-Eye technology that powers ABS to determine whether a first down has been reached, doing away with nearly a century of the chain gang. The NBA, which has a history of gambling referees and a more recent scandal involving players and coaches, has rolled out a tool they call “automated officiating,” which reduces the role of the on-court official for certain calls. 

Leagues have pitched these rule changes as ways to ensure the integrity of their sports while dealing with the reality of legalized gambling. While this may be true, these leagues are businesses, and everything they do is done with profit in mind. The changes arguably benefit everyone: “[l]eagues get cleaner broadcasts, sponsors get fewer PR train wrecks, and betting markets get a more predictable product — because [betting] lines can move when strike zones shift even slightly,” but profit is the determining factor. 

The leagues and sportsbooks know that being able to wager on a game makes people more likely to watch. One of the most popular forms of sports betting is live betting, which allows bettors to place wagers mid-game, and as The New York Times reported, “[l]eagues see it as a way to get fans to watch more games for longer periods, which drives up the price of media rights deals.” Both the MLB and NBA allow a limited number of in-game gambling advertisements as well. “Michael Kay, the New York Yankees play-by-play announcer…will offer odds or set up predictions and direct viewers to a sportsbook that sponsors the broadcast and takes the bets.” While MLB and other sports leagues attempt to paint a picture of responsibility and integrity, they are simultaneously encouraging the very activity threatening the integrity of sports, all while tailoring the rules as a means to their desired ends. 

Major League Baseball’s introduction of ABS is a clear marker of how the league is adapting to the new reality of legalized sports betting. While the reform has legitimate officiating aims and likely will improve the viewer experience, it cannot be isolated from the broader context of leagues seeking to benefit financially from their symbiotic relationship with sportsbooks. The adoption of ABS fits well within the trend of leagues seeking greater integration with sportsbooks, richer data monetization, and more betting-friendly production of games. Whether this trend ultimately improves sports or further opens the door to questions of integrity remains to be seen. However, it is clear that MLB and professional sports leagues broadly are embracing betting as part of their business strategies, and ABS is just one technological piece of that shift.

*The views expressed in this article do not represent the views of Santa Clara University.