Baseball’s Data Revolution
Alum Mike Petriello is helping Major League Baseball reinvent the way we understand the national pastime
For as long as baseball has been played, statistics and storytelling have been intertwined. Henry Chadwick, a newspaper journalist, published the first box score in 1859. By summarizing common events like hits, runs, and strikeouts, he created a way for people to follow the game in the era before radio or television broadcasts. When John Updike wrote one of the most famous baseball stories of all time—“Hub Fans Bid Kid Adieu,” which appeared in the October 22, 1960, issue of The New Yorker—he peppered his prose with batting averages and home run totals to explain the greatness of Red Sox left fielder Ted Williams. And, in 2015, as Major League Baseball was introducing digital technology that would revolutionize the professional game, they looked to an heir to Chadwick’s legacy to explain it to the public: a baseball blogger.
Mike Petriello grew up a baseball obsessed kid in New Jersey. He rooted for the Los Angeles Dodgers—“because the Yankees were terrible in the ’80s”—and played Little League. “Baseball has been it since day one,” he says. He went to BU in part because of its proximity to Fenway Park, although a career in the game didn’t seem realistic in the late 1990s.
Petriello (CAS’03) majored in history and worked in video production after graduation. He began writing about the Dodgers in 2007 as a hobby. “At that time, talking about stats was unusual,” he says. “And what I was trying to do was talk about them in a way that was filled with Simpsons jokes—accessible and entertaining and not sounding like algebra class.” That mix of humor and hard data attracted attention in the burgeoning world of baseball blogs. Petriello landed assignments from analytically inclined sites like the Hardball Times and FanGraphs, and from ESPN. When his ESPN editor jumped to Major League Baseball (MLB), he offered Petriello a freelance gig covering Statcast, the advanced statistics technology the league was developing.
Now MLB’s director of stats and research, Petriello is at the heart of baseball’s data revolution. Over the past decade, MLB has introduced technologies that quantify everything from the mesmerizing 20-inch horizontal break of a Paul Skenes sweeper to the record-breaking 122.9 mile-per-hour velocity of the ball off Oneil Cruz’s bat.
The data the league collects can help players train more effectively, allow teams to better scout opponents and evaluate talent, and even be used to identify injuries. The same digital technology that produces this data has also placed professional baseball on the cusp of one of the biggest changes in the history of the game: so-called robo umpires, which were used during the 2025 MLB All-Star Game, and will be used in a limited role in the 2026 regular season.
And when the league rolls out a new statistic or metric, Petriello is responsible for introducing it to the public. “If I had to pick one word to describe what I do, it would be ‘translator,’” he says.
Big (League) Data
In the early 2000s, officials within MLB started to consider the audacious goal of creating a new generation of stats that could quantify every movement on a baseball field. The only problem was, the technology didn’t exist yet.
The first big step in that direction came in 2007. The league installed PITCHf/x cameras in all 30 major league ballparks, recording the velocity, location, and type of every pitch. In 2015, the league added a radar-based system that could measure the velocity of the ball off the bat and calculate the distance of a home run. High-speed Hawk-Eye cameras have since allowed them to measure things like batters’ body positions and pitchers’ arm angles.
By 2015, MLB already had a roster of in-house writers covering local and national beats, but they needed someone fluent in baseball metrics to write about Statcast. As the league prepared to release its first new metrics to the public, it hired Petriello. Over time, he has become much more than a writer. He collaborates with the league’s engineers and data scientists, developing new stats. “Any of us can come up with an idea,” he says. “And it always starts with crafting what the thing should be, what story we’re trying to tell. Is it going to be presented in a percent or in time or in distance?” Done well, that information helps everyone interested in baseball—from the fans in the stands to the players on the field—understand the game better.
Raw Statcast data is shared with all 30 MLB teams who feed it into proprietary systems they use for player development and scouting. This can help pitchers design new pitches, hitters reinvent their swings, and fielders position themselves optimally. “They’re using this information to help some of the best athletes on the planet get better,” Petriello says.
If I had to pick one word to describe what I do, it would be ‘translator.’
MLB makes some of this information available to the public via its Baseball Savant website. There, with a few clicks, readers can splice data in countless ways—sorting leaderboards, looking at heat maps of individual player tendencies, and scrolling through futuristic box scores. No coding background needed. They can also read the analysis of MLB writers like Petriello.
When the Statcast team unveils new metrics, Petriello typically writes an introductory story that’s packed with video clips and graphics to explain the stats and showcase the players who are best at the skills they quantify. In March, he used new data to highlight baseball’s most extreme batting stances. Who stands closest to home plate or farthest away? Which batters take the largest stride toward the pitcher or barely any stride at all? Two months later, he introduced metrics—including swing path and attack angle—that describe the shape of a hitter’s swing.
“Across the sport, players are using data and technology to improve their own games,” Petriello wrote. “All you have to do is just listen to them tell you about it.” He quoted the Arizona Diamondbacks star Corbin Carroll, who had adjusted his attack angle—the angle of the bat’s path as it meets the ball—between his lackluster first half of 2024 and his strong second half and start to 2025.
Promoting the Future of the Game
While Baseball Savant may be a sandbox for only the most analytically inclined fans, Petriello is also a resource for the frontlines of baseball media: the beat writers and broadcasters who cover baseball daily.
Boog Sciambi, play-by-play announcer for the Chicago Cubs and ESPN, says he feels an obligation to explain advanced metrics to his audience—and he receives a weekly info packet from Petriello for ESPN Radio’s Sunday Night Baseball broadcasts to help him do so. “That’s the way front offices are building their rosters,” Sciambi says. “This is the stuff that matters.”
Jason Benetti, television play-by-play announcer for the Detroit Tigers, says, “Mike is brilliant at finding the information which tells the story of why each player is on the field. He makes the analytical human.”
It’s a critical skill, given the overwhelming amount of information that MLB collects. Baseball’s statistical story used to be recorded by hand; now it’s parsed from terabytes of data. The Hawk-Eye system records every game with a dozen cameras recording 50 or 300 frames per second—that’s more than 110,000 frames per minute for two-plus hours each game. That gives the Statcast team a massive collection of data to work with.
As the 2025 season unfolded, they followed up their new swing metrics with data about catcher stances, and Petriello was already looking ahead to new stats that would quantify which pitches miss the bat by the most.
MLB has experimented with using Hawk-Eye for some ball-and-strike calls. In 2026, the league will introduce the Automated Ball-Strike (ABS) system to regular season games by allowing players to challenge umpire calls on the field. ABS is sure to change the game in complicated ways—but Petriello and his colleagues will be there to explain the how and why.