Major League Baseball’s exhibition season gets underway Friday afternoon. Unlike most years, this round of spring training isn’t just serving as a warm-up for the players, but rather will also serve as the final rehearsal before the new automated ball-strike challenge system is implemented during the regular season.
Indeed, for the first time in MLB history, technology will be used in games to verify balls and strikes. To be clear: technology will not be calling every ball and strike. This is, instead, a compromise between a fully automated system and a fully human approach. Teams will be afforded a set number of challenges per game, which they can then exercise at their will.
Such a momentous occasion deserves a closer examination. Below, CBS Sports has provided an answer to all of the questions you may have concerning the ABS, including how it works and how often calls have been overturned. Let’s get to it.
1. How does ABS work?
Essentially, it makes use of advanced camera and limb-tracking technology to create an individualized strike zone for every batter. As an engineer familiar with the inner workings of the system outlined in 2021, from there the system is really a collection of four subsets:
- The MLB tracking system;
- An interface the ballpark operator uses to set the correct batter;
- An MLB server that receives the tracking data and has the ball-strike evaluation code;
- A low-latency communication system to relay calls to the umpire.
One key component of the ABS system is that measurements of each player will allow the technology to render specific strike zones, rather than a generalized zone.
Baseball America has explained that process in the past: “The new zone will mean each player’s strike zone is uniquely tied to their body and stance rather than a universal formula. The new strike zone is hoped to more closely resemble the strike zone used by human umpires, although the top end is still designed to be lower than the top end of the MLB strike zone.”
2. What are the in-game guidelines?
As the “challenge” aspect of the name suggests, teams are limited to two challenges per game. They can be used at any time, on any pitch. Teams will keep their challenges if they are successful, but do note that the dugout cannot initiate challenges. Instead, they must come from either the batter or the battery. Last spring, batters often tapped their helmet to call for a challenge.
Teams will be awarded one additional challenge at the start of every inning beyond the ninth, but those do not roll over or accumulate if they are successful or unused.
Per MLB guidelines, a pitch can be subject to both an ABS challenge and a replay challenge — think a called strike (or ball) that precedes a throw on an attempted stolen base.
3. Has ABS been used before?
Yes, as you would expect given the stakes. MLB tested a few approaches to the ABS system in the minors in recent years, including full automation. They’ve also experimented with the challenge system at the big-league level, albeit only in exhibition settings to date (last year’s spring training and the All-Star Game), as a means of stress-testing the technology with an audience of big-league personnel. Those tests went off without a hitch, clearing the way for full-time implementation.
4. How long does it take and how often are calls overturned?
If you haven’t seen the challenge system at work yet, don’t fear: it’s not like replay challenges, where the process can linger and slow down the game for minutes at a time. The ABS system is quick and painless, offering a resolution within a matter of seconds. Here’s an example of it at work:
So far as the other part of the subheading goes, all available data suggests it would be reasonable to expect a success rate around 50%. MLB released data last year showing that 52.2% of challenges during spring training were successful. Meanwhile, TruMedia’s minor-league data had the MiLB success rate around 49%. Obviously the exact overturn rate will fluctuate based on the strategies
5. Anything else worth knowing?
Yes, and it’s arguably the most important aspect of the whole operation: MLB will not permit challenges whenever a positional player is pitching. Sorry to those who wanted to see a particularly challenge-happy hitter receive a taste of his own medicine.
