Bats Disappearing: How an excessive focus on strikeouts disrupted the equilibrium of baseball

Missing Bats, a special series this week in The Athletic, explores how baseball’s profound metamorphosis over the last two decades traces back to one simple idea — maximizing strikeouts at all costs — that became an industry-wide obsession. Explore the entire series here.

As a boy pitching on Little League fields in the suburbs of Los Angeles, Tyler Glasnow fixated on missing bats.

“Ever since I was a child,” Glasnow said, “any time I ever touched the mound, I just wanted to strike everyone out.”

Glasnow, a 6-foot-8, 225-pound starting pitcher for the Los Angeles Dodgers, grew to be taller than almost all of his teammates, with longer limbs but less control of his frame. Growing up in the first decade of the 21st century, pitchers were taught to value the same things pitchers prioritized in the 20th century, searching for soft contact and quick innings. An at-bat should not last longer than three pitches — a mantra that was harder for someone like Glasnow to apply. When he tried to be precise, bridling his body to control the location of his pitches, he lost his command. He was better served, he realized, trying to throw the baseball past the opposing batter and through the catcher, as hard as possible, as fast as possible, every single time.

He did not need soft contact if the hitters never made contact. In his mind, he conjured up a new ideal to chase.

“The perfect inning for me,” Glasnow said, “is nine pitches, nine strikes, three strikeouts.”

The simple concept Glasnow grasped as a child has come to reshape the game he plays as an adult. Like the embrace of the three-point shot in basketball or the advent of the downfield pass in football, modern baseball’s obsession with strikeouts has led to a jarring transformation.

For baseball to be its most compelling, the battle between hitter and pitcher must be waged on equal footing, and for most of the past century, the game didn’t stray too far from this fundamental stasis. But that balance has been upended by the primacy of the strikeout. The concept of pitching to contact has gone the way of the mid-range jumper. “Three pitches or less” sounds as antiquated as “three yards and a cloud of dust.”

Like the corner trey or the deep ball, missing bats makes intuitive sense. A pitcher who could generate strikeouts was always a valuable asset. What separates this era from its antecedents is that the skill is no longer limited to a small group of outliers, blessed with a god-given talent that can’t be taught. In the past 20 years, the industry has learned instead that it can create pitchers who can pile up strikeouts, with entire organizations churning them out with assembly-line efficiency.

“Pitchers are a lot more malleable than we initially thought,” New York Yankees pitching coach Matt Blake said. “Obviously, if you could strike guys out, that was exciting. But I don’t think we understood the true value of swing-and-miss.”

That realization affected the game’s rules, its best practices and its developmental pipeline. Teams rebuilt pitchers’ bodies to chase velocity, used biomechanical analysis to maximize spin rate, and altered pitching strategies to emphasize attacking with high fastballs as the desperate pursuit of strikeouts spread throughout the league like a virus.

For years, the symptoms of that viral spread have been discussed on nearly every baseball broadcast, and debated by those who fell in love with a different game. This week, The Athletic will explore the root cause of baseball’s metamorphosis: the concept of missing bats, from the origin of the idea, to the recognition of its value, through the widespread application of its importance, and ultimately to the cost of its proliferation.

These stories emerged from dozens of interviews with players, coaches, executives and analysts. The shift predates the so-called “launch angle revolution” of the mid-2010s, in which hitters started to sacrifice contact in search of slugging. The origins of the transformation involve a collection of curious outsiders, enraptured by access to an influx of data, and a handful of desperate lifers, clawing for a foothold in a ruthless game. The curious informed the desperate. The success of the desperate made others more curious. The subsequent feedback loop altered the course of baseball history.

The spiderweb of consequences from that shift reflects a new reality: The sport looks different than it did two decades ago because pitchers know how to miss bats, and strikeouts are now a prerequisite for big-league consideration.

“If you want to be a successful pitcher, you have to have strikeouts,” Arizona Diamondbacks pitching coach Brent Strom said. “You need some semblance of swing-and-miss.”

In 2006, the season before Major League Baseball began installing advanced pitch-tracking systems in all 30 big-league stadiums, the league-wide batting average was .269. By 2011, the year Glasnow was drafted by the Pittsburgh Pirates, as insight from the data trickled through front offices, the average had fallen to .255. The average plummeted to .243 in 2022. The strikeout rate has followed an inverse path: 16.6 percent of at-bats ended in a strikeout in 2006, 22.7 percent did in 2023. To increase offense and liven up the product, MLB last season introduced a pitch clock and placed restrictions on infield shifts; that helped bring the league-wide average back up to .248.

The rule changes could only do so much. Teams have learned the value of increased fastball velocity and breaking ball movement, wielding technology to heighten those qualities. An obsession with generating spin and velocity led to a reliance upon illegal foreign substances which led to a 2021 crackdown on “sticky stuff” which some players — including Glasnow — believe ultimately led to an uptick in arm injuries. This season, as MLB officials kvetched about another rash of arm surgeries to open the season, there was another round of dialogue about the reasons for all the pitching problems.

The answers all stem back to discoveries made years ago, when the curious began to inform the desperate. The scenes of innovation take place in locations both obscure and understandable: A psychology department in Iowa City. A ballpark office in St. Petersburg, Fla. A garage in the San Francisco Bay Area. A mound in a packed stadium in Houston. Together, they help explain why baseball looks the way it does in 2024.

“You’ll see a lot of people who played in earlier decades waxing poetic about ‘Guys shouldn’t be striking out as much’ or ‘We need to make more contact,’” Chicago White Sox senior advisor Brian Bannister said. “It’s not that the hitters aren’t trying to do that. It’s just really hard to hit a baseball. It was always the hardest thing to do in sports. And then we made it even harder.”

Dan Brooks did not intend to make his surname ubiquitous with strikeout rates. He was just trying to help a buddy struggling with Microsoft Excel.

By 2008, all 30 big-league stadiums featured a tracking system called PITCHf/x. Built by Sportvision, the company famed for generating the yellow first-down lines on football broadcasts, PITCHf/x utilized a triangular camera setup to detect each pitch’s velocity, release point, location, and horizontal and vertical break. The system logged pitches with more detail than ever before, a treasure trove for the burgeoning group of curious baseball fans searching for deeper insight into the game.

The data was publicly available if you knew where to find it. Brooks, an experimental psychologist studying for his PhD at the University of Iowa, knew where to find the data. And unlike his friend, he also knew how to use Excel to scrape the data. This PITCHf/x data would become the foundation for a website featuring sortable charts and tables that cataloged pitch types and their individual characteristics. The site also grew to include a real-time plot of the strike zone for games. It became a destination for enthusiasts. He called it BrooksBaseball.net, which, he mused years later, was “useful from a personal marketing standpoint, to whatever use that is in life.”

The PITCHf/x data offered answers that people in baseball had sought for decades. The usefulness of strikeouts was never a secret. The statistical guru Bill James had evangelized the value of missing bats since the 1980s. Sandy Koufax fanned more than a batter per inning in his five-season renaissance; Nolan Ryan did the same across a 27-season career. Randy Johnson captured five Cy Young Awards while finishing his career by averaging 10.6 strikeouts per nine innings. Before injuries capsized his career, Chicago Cubs phenom Mark Prior punched out hitters at the same rate as Johnson. “I had swing-and-miss stuff,” Prior said. “So I tried to lean into my strengths.” Most games, Prior recalled, “I tried to strike out the side every first inning.”

The conventional wisdom in the industry, however, suggested that only a certain type of pitcher could chase whiffs. The pitcher needed to harness elite weapons like Koufax or boast remarkable stamina like Ryan or pitch from a hellacious angle like Johnson. The average man could not produce those results — even if a studious, dedicated pitcher could figure out how to get into advantageous counts.

While poring through the information, Kalk applied the Nash equilibrium, a game-theory concept gleaned from the world of mathematics, which posited that an individual could formulate an optimal strategy no matter the strategies of the opponents. (The concept was memorialized in the film “A Beautiful Mind” during a scene in which Russell Crowe as the mathematician John Nash asked, ‘What if no one goes for the blonde?’”) Applied to baseball, the principle suggested each pitcher possessed an ideal, individualized mixture of pitches. The percentages depended on the strengths and weaknesses of each pitcher. The proximity to equilibrium would appear in the data if the results of each different pitch were identical. Because of PITCHf/x, the analysts could now measure the effectiveness of each individual offering.

What Kalk discovered was that very few, if any, big-league pitchers approached this equilibrium. One of the first to come close was James Shields, a pitcher with a plethora of weapons. Shields could throw three different types of fastballs and an elite changeup. After a rocky season in 2010, though, Tampa Bay officials suggested he throw his curveball more often. Shields raised his curve usage from 13.5 percent to 21 percent in 2011 and achieved the best results of his career, making the All-Star team and leading baseball with 11 complete games. “Every year, we were always making adjustments to be able to pitch in (those) ideal pitch sequences, so that you’re not predictable,” Shields said. The Rays ranked 15th in baseball in strikeout rate in 2011 (7.11 strikeouts per nine innings); across the next three seasons, the team zoomed to first (8.47 strikeouts per nine).

Kalk worked remotely from West Virginia. After a few years, the Rays asked him to venture into the field more often. The team wanted to spread his wisdom across the organization. Friedman introduced Kalk to Kyle Snyder, a towering former first-round pick who Tampa Bay hired as a class-A pitching coach in 2012. A year later, when Snyder was promoted to coach at Double-A Bowling Green, Kalk sat him down. Kalk had prepared a PITCHf/x plot culled from Snyder’s own career, which ended in independent ball in 2011. The analyst showed the former athlete all the ways in which he could have pitched differently, had he known about the data. “It was one of the more powerful things for me in terms of not just my buy-in,” Snyder said, “but realizing how powerful this information was about to become.”

Kalk flipped past the page dedicated to Snyder and unveiled similar plots for Tampa Bay minor-league pitchers like Dylan Floro, Taylor Guerrieri and Jesse Hahn. Each plot contained clues for optimizing pitchers — not just which of their pitches were best, but why. “I’m like, I cannot believe what I’m looking at and how powerful this is in terms of just understanding physics and how the balls move,” Snyder said.

A year later, Snyder became the organization’s minor-league pitching coordinator. He reveled in his trips to the team’s Appalachian League affiliate in Princeton, W. Va., because the site was near Kalk’s home. Like so many in his profession, Snyder sought clarity on the most effective way to procure 27 outs. Kalk shined the light.

“I started peppering him with questions after I realized the asset that he was,” Snyder said. “I’m like, ‘Wait a second, man. Let’s start talking about this.’” The conversations opened Snyder’s eyes. There was no out more effective than a strikeout. “I’m like: OK, other than a ball getting to the backstop on a wild pitch or a passed ball, if a guy swings at strike three, he’s out!”

That was not exactly a secret. In “Moneyball,” published in 2002, the author Michael Lewis had highlighted the work of sabermetrician Voros McCracken, who discovered that pitchers had little control of the results once a ball was put in play. As that theory took root, pitchers used the PITCHf/x data to hone the most direct method to regain some measure of control.

“If you want to be an effective pitcher at the major-league level, what’s the most effective thing to do? Don’t let guys get on base,” Click said. “What’s the most effective way to do that? Don’t let them hit the ball.”

To miss more bats, though, you had to answer a more fundamental question: What is an effective pitch at the major-league level? For that, they turned to Kalk. The team invited him to spring training in 2009 and convinced him to leave academia. “I remember all of us sitting around, saying, ‘This guy’s doing some pretty cool (stuff),” Click said. “We should probably see if he’s interested.’”

Like his new teammates, Kalk was a curious fellow. He disdained attention; he declined an interview request for this story. He held a master’s degree in physics from Michigan State. In his day job as a physicist, he studied the so-called “top quark,” once described as “an ephemeral building block of matter that probably holds clues to some of the ultimate riddles of existence.” In baseball, there were similar, if less existential, depths to the influx of pitch-level data.

For much of the sport’s history, a pitcher’s repertoire often stemmed less from his physical capabilities and more from his organization’s preferences. Some teams emphasized changeups and curveballs. Others favored sliders and sinkers. The Rays tended to instruct pitchers to attack hitters on a vertical plane rather than a horizontal plane, because the strike zone was taller than it was wide. But one size did not fit all. Anyone who has attempted to fit a square peg into a round hole can understand why this paradigm was not ideal. Yet few challenged it, in part because it was unclear how to formulate a precise plan for an individual.

While poring through the information, Kalk applied the Nash equilibrium, a game-theory concept gleaned from the world of mathematics, which posited that an individual could formulate an optimal strategy no matter the strategies of the opponents. (The concept was memorialized in the film “A Beautiful Mind” during a scene in which Russell Crowe as the mathematician John Nash asked, ‘What if no one goes for the blonde?’”) Applied to baseball, the principle suggested each pitcher possessed an ideal, individualized mixture of pitches. The percentages depended on the strengths and weaknesses of each pitcher. The proximity to equilibrium would appear in the data if the results of each different pitch were identical. Because of PITCHf/x, the analysts could now measure the effectiveness of each individual offering.

What Kalk discovered was that very few, if any, big-league pitchers approached this equilibrium. One of the first to come close was James Shields, a pitcher with a plethora of weapons. Shields could throw three different types of fastballs and an elite changeup. After a rocky season in 2010, though, Tampa Bay officials suggested he throw his curveball more often. Shields raised his curve usage from 13.5 percent to 21 percent in 2011 and achieved the best results of his career, making the All-Star team and leading baseball with 11 complete games. “Every year, we were always making adjustments to be able to pitch in (those) ideal pitch sequences, so that you’re not predictable,” Shields said. The Rays ranked 15th in baseball in strikeout rate in 201