Baseball ushers in high-tech replay review system for calling balls and strikes

For more than a century, baseball home plate umpires have called a ball or strike based on the interpretation of a vague, vaguely defined strike zone.

Subjective calls decided at-bats, games, seasons and pennants – and, naturally, sparked endless debate.

Now, for the first time this season, Major League Baseball is instituting a review system in which players can challenge ball strike calls. Meaning: For the first time, the strike zone will be defined and there will be a definitive answer to the debate.

The Automated Ball-Strike (ABS) Challenge System, which has been tested in the minor leagues and at MLB spring training, will debut Wednesday night in the MLB season opener, when the San Francisco Giants host the New York Yankees – coincidentally in America’s high-tech capital.

After each pitch, when the umpire calls the ball or strikes, there will be a two-second window during which the batter, pitcher or catcher can issue a challenge.

Once a review is requested, the stadium scoreboard will indicate the system’s decision as to whether the pitch has crossed the strike zone. Everyone will have to wait with bated breath, like in tennis with incoming and outgoing call challenges.

Each team will have two challenges per match and will keep them if they are correct.

For baseball to create its system, MLB had to definitively define its strike zone, which has been a moving and subjective target since the dawn of the game.

As far as rule changes go, this is a massive change for baseball, one that is expected to change gameplay and strategy, much like when the American League adopted the designated hitter in the 1970s.

“I think [the ABS system] is more important than the DH and even more important than the foul rule at the turn of the last century,” MLB historian John Thorn told NBC News.

What is the new strike zone?

Before Wednesday night, throughout baseball history, the strike zone was very subjective, right down to the umpire’s judgment. A strike had more recently been defined as the area above home plate, bordered at the top midway between “the batter’s shoulders and the top of the uniform pants”, then at the bottom at “a point just below the kneecap”.

“Umpires have traditionally called something flexible, right? It depends on the count, the game situation, the score, all those things,” MLB vice president of on-field strategy Joe Martinez said. “The strike zone tends to expand and contract based on that kind of thing.”

Now, when a ball striking decision is challenged, the strike zone will be rigidly defined based on the size of the batter. A strike is now defined as a pitch that passes over home plate and is between 27% and 53.5% of the batter’s height.

Under the new system, if a contested pitch cuts off part of that imaginary “window” that is practically based in the middle of home plate, it will be called a strike, Martinez said.

What are the issues?

Why does baseball need a replay overhaul?

Look no further than the recent World Baseball Classic. A semifinal between the United States and the Dominican Republic ended with a predicted third goal, on a pitch that appeared well outside the zone.

The pitch “was 3 inches below the zone; [a replay system] could have changed everything,” Miami Marlins catcher Liam Hicks said. “So I hope [ABS] avoids making mistakes at certain big moments. So I think I’m a fan of it.

But even a missed call that isn’t a ball four or a strike three can have a profound impact. For example, when the count is 2-1 and the batter does not swing at a boundary pitch, his fate will be drastically changed by the ensuing call.

When a ball was called and the batter took a 3-1 count lead, last year’s batters had a .255 batting average, .592 on-base percentage, .453 slugging percentage and 1.045 OPS. Or, in other words, this ordinary hitter, with a 3-1 advantage, has become the equivalent of world slugger Shohei Ohtani, who posted a 1.014 OPS last season.

But if the umpire called a strike and the score came back to 2-2, everything went to the pitcher’s side. The slugger, at 2-2 last year, continued with a microscopic .178 batting average, .286 on-base percentage, an anemic .291 slugging percentage and .577 OPS.

Of all MLB hitters last year with enough qualifying plate appearances, Milwaukee Brewers shortstop Joey Ortiz recorded the lowest OPS (.230/.276/.317), at .593.

What is the strategy?

Interestingly, players will have to decide if they want to compete alone. They can’t take advice from coaches, teammates or thuggish fans shouting from the stands.

“A player’s decision to challenge must be made without assistance” and “if someone is yelling from the dugout, if another player is on the field and is banging his head, the umpires have the ability to decline a challenge,” said Martinez, the MLB executive.

Each team can continue to fight until they mess up twice, so valuable calls should not be used willy-nilly.

Miami Marlins manager Clayton McCullough said his team would discourage his pitchers from throwing challenges, even if they are allowed, leaving the decisions up to the catcher. The pitcher stands about 60½ feet from home plate, after all, much further than the catcher.

“Our pitchers won’t be able to contest,” McCullough said. “We’ll put a lot of emphasis on all of our catchers being very good at it. That’s led us to create training environments for them in camp, our catcher in particular, to spend a lot of time practicing with an automated strike zone.”

In Triple-A last year, challenges were 50% successful, and they were 51% successful the year before.

This spring, most major league players and managers said they plan to save calls for late innings and other key moments of the game, known as “high leverage” situations.

In Triple-A games last year, the highest percentage of challenges occurred in the ninth inning (3.5 percent of all pitches called), and the lowest percentage occurred in the first inning (just 2.1 percent).

“[What] We’ve tried to emphasize to them during this camp that yes, we would like to be the most effective at overturning calls,” McCullough said. “And probably more importantly, we want to be challenging at the most appropriate times.”

But counterintuitively, first-year San Francisco Giants manager Tony Vitello said he wouldn’t mind if his players were more aggressive in using challenges, even early in a contest.

“I think the biggest thing is you don’t want to leave them on the table,” said Vitello, a highly successful coach at the University of Tennessee who is considered the first MLB manager without prior big league experience.

“If you see something that makes you feel like, ‘No, I know for sure that’s wrong,’ you might as well give it a try.”

Learning curve for fans

During a spring training game last week between the St. Louis Cardinals and Miami Marlins, many fans contacted by NBC News had no idea that MLB had installed the challenge system for 2026 — even though a pregame tutorial was broadcast on the scoreboard at Roger Dean Chevrolet Stadium in Jupiter, Florida.

“I’m a traditionalist and I don’t like it,” said Dallas resident Heather Garrison, who was at the game to see her son, Marlins bullpen catcher Tanner Garrison. “I like the old way where you trust that they’re going to make a call and you follow through with it and in the end everything works out equal.”

Another Jupiter fan that day, Jordan Waxman, said he would prefer any challenge decisions be made by a human rather than a computer, as in the case of safety/out calls reviewed at MLB’s replay center in New York.

“I don’t like [the new replay system]. I don’t like anything to do with AI,” Waxman said. “The game is over 140 years old and they never needed it until now. It just takes away from the story of the game. I’d rather they call New York for a challenge than have it computerized. You’re starting to involve computers, so what’s next? »