The 1-and-2 pitch to Rangers slugger Joey Gallo last Sept. 17 didn’t signify the start of a revolution—it was more the Second Battle of Saratoga than Lexington and Concord. The first shots had come a few years earlier, igniting the greatest hitting rebellion since Babe Ruth (more or less) invented the home run. What happened on this pitch in Anaheim would confirm the strength of the revolutionary forces.

The delivery from Angels righthander Garrett Richards was most likely to be a slider: He used that pitch 75 of 178 times with two strikes last season, giving up just two singles. Behind him, the shortstop crouched near second base, the second baseman in short rightfield and the first baseman far in back of the bag. To crack this analytics-crafted cordon with an opposite-field ground ball would require the exactitude of Tom Cruise in the vault scene from Mission: Impossible, especially for Gallo, a 6' 5" lefthanded, launch-happy first baseman. In 2017 he swung at 1,056 pitches. Only once—a certifiable mistake—did he ground a single to left.

A generation ago a batter facing a 1-and-2 pitch would shorten his stroke to put the ball in play. Only four years ago he would be quick to the ball by getting on top of it with a steep swing path—the approach he had taken repeatedly in practice to fire shots with the trajectory of a clothesline at the back net of the batting cage.

Not now. Not since the early adapters and the quants learned that much of the orthodoxy of hitting was stone-cold wrong. A steady decline triggered by more stringent performance-enhancing drug testing had sent offenses into a tailspin. By 2014, runs and batting average were at their lowest since the introduction of the DH, in 1973.

Opening Day is nearing. Prepare by binging on baseball classics like Bull Durham and Bad News Bears, only on SI TV. Start your 7-day free trial now.

Then came the revolution—an insurgency waged in the air. In just three seasons, from 2015 to ’17, batters hit 3,023 fewer ground balls and 1,196 more home runs, including a record 6,105 dingers last year. There were 3,157 more fly balls and few complaints about the tariff for all that lifting: 2,658 more strikeouts. Teams scored 4.65 runs per game in ’17, up from 4.07 in ’14.

Baseball is supposed to ebb and flow like the tides; change, moment to moment, is often barely perceptible. But this? This was the Angel Falls of change, a stupendous cascade. The traditional tenets of hitting flipped quickly.

Be quick to the ball? No. Get ready early and slowly tip the bat back before firing.

Get on top of it? No. Use a slightly upward path to strike the bottom third of the ball.

Hit the fastball out front and the breaking ball deep? No. Do the opposite.

Hit the ball to the back of the batting cage? No. Hit it toward the top.

Just put the ball in play? No. Always try to get it in the air, even at the risk of whiffing.

A confluence of three forces has changed offenses radically: technology, analytics and failed ballplayers turned private hitting tutors—the veritable garage-and-basement indy start-ups of this disruption. Among them: a 71-year-old college dropout cum surfer, a former high school coach, a failed independent league player, a self-taught Internet baseball junkie and a .204 hitter who was released from Class A ball after just two seasons and four home runs. Not a major league at bat among them.

They have something else in common: freedom from industry bias. Hitting concepts were once passed down like stories at the Thanksgiving table, generation to generation. These outsiders have instead used technology not just to educate themselves but also to disseminate their message, guiding the celebrated midcareer breakthroughs of J.D. Martinez, Justin Turner, Josh Donaldson and Jake Marisnick—to name just a few.

Gallo never had to change. He was skying balls before it was cool. As a kid in Las Vegas he fell under the tutelage of Mike Bryant, the father of one of his travel teammates and best friends, Kris Bryant, now the Cubs’ third baseman. In 1980 and ’81, Mike hit .204 in the Red Sox’ system before they released him—but that came after Ted Williams imparted to him the importance of hitting the ball in the air with a slightly upward swing path.

“When I was eight years old, Mike was teaching me to hit the ball to the top of the cage, but not by dropping my shoulder,” Gallo says. “It was more backspinning the ball. With every coach I had besides Mike, we were hitting ground balls to shortstop as a lefty, or as a righty hitting them to second base. A lot of those guys are in the minors now. They still have that same kind of swing, and they’re trying to change. But for me, I always had that [loft]. I kind of credit my career to Mike. We were at the beginning of that new-era hitter.”

Last season Gallo went deep 41 times, joining Reggie Jackson, Ken Griffey Jr. and Hal Trosky as the only lefthanded hitters to surpass 40 in the American League by age 23. Bryant has mashed 94 homers in his first three seasons, sixth most in National League history.

Says Bryant of his father, “He got it early. I’m sure if he wasn’t in the Red Sox organization with access to [Williams], I don’t know if he’d be teaching this way, or at all. It’s so funny. Back then it was, ‘Mike Bryant, he doesn’t know what he’s doing.’ Now everybody is saying exactly what my dad said.”

***

Richards threw his slider down and in, as confidently as British general John Burgoyne must have been when he decided to test the Continental Army at Saratoga. Gallo is the King of Loft. No qualified hitter last year connected with a higher average launch angle (the trajectory of the ball off the bat) than Gallo’s 22.3 degrees—more than twice the major league mean. He batted .458 on balls in the air and .164 on balls on the ground. Only Matt Carpenter of the Cardinals (73.1%) got the ball airborne more often than Gallo (72.1%).

Gallo’s approach at 1 and 2 was the same as when he first stepped into the box, the same one he learned in Mike Bryant’s cage: backspin the tar out of the ball and send it skyward to centerfield. Such intransigence also is why he has struck out 272 times in his first 198 career games, more than anybody in history except one of his contemporaries, Twins third baseman Miguel Sanó. Over three seasons Gallo has a .201 average. “A lot of people disagree with that approach,” he says, “and I get bagged on a lot for that, but that’s just how I am. I’m going up there and taking my ‘A’ swing every time.”

As Gallo uncoiled, a huge and growing army of kids were mimicking his stroke in batting cages, the tops of which either had rings dangling as targets or a bright line 17 feet away to mark the impact of a ball launched at 25 degrees, the sweet spot for a homer. They were batting off “Launch Angle” tees designed to expose the bottom of the baseball as the ideal contact point. They were paying $100 an hour for lessons, wielding $400 metal bats outfitted on the knobs with $150 swing analyzers and connected to $20,000 motion detection systems.

“I think we are at the beginning,” says Craig Wallenbrock, the former surfer who is more likely to quote Wu Li, a 17th-century Chinese painter, priest and philosopher, than legendary hitting guru Charley Lau. “From the ’60s through the ’80s things didn’t change much, with the bat in and out of the zone quickly. In the ’90s things started changing a bit. Within just the last three years we’ve seen incredible change because of technology. Baseball always has changed. But now that change is coming faster.”

***

Imagine a globe hanging in front of home plate, and a hitter swinging a sword at it, envisioning its core as the sweet spot of contact. Traditionally, a batter would be trained to bring his hands from their starting position toward the globe as quickly as possible in a direct, downward line. He’d try to strike the globe with the sword just north of the equator, continue down to the sweet spot at the core and then turn upward after contact—exiting the other side of the globe still in the Northern Hemisphere, without the sword ever crossing the equator. Hitting instructors called this the classic “in and out” swing path.

As recently as 2013, in comments to Fangraphs.com, then Tigers hitting coach Lloyd McClendon and Red Sox assistant hitting coach Victor Rodriguez recommended this downward trajectory. McClendon: “You want to focus on the top half of the ball ... and work your hands down through the ball.” Rodriguez: “You want a direct path to the ball and to hit the top part.” The idea was that you could enhance distance by imparting backspin if you clipped the ball just right—like a wedge hitting a golf ball and then the turf. McClendon and Rodriguez were not just any hitting coaches: They worked for the two highest-scoring teams in baseball that year.

This technique was standard practice. It also created a small window for optimal contact because the bat was in and out of the strike zone quickly. The average MLB fastball starts out six feet, one inch off the ground at 92.5 mph. By the time it reaches home it typically is two feet, seven inches off the ground and traveling at 85.2 mph. The drop of 42 inches creates a six-degree angle of decline. (Curveballs drop by at least 10 degrees.) A downward swing to meet a dropping pitch often produces contact on the top of the ball, resulting in grounders, which are outs 75.5% of the time.

Meanwhile, two trends were rendering the in-and-out approach even less effective. First, velocity ramped up. From 2002 to ’14 the average fastball jumped from 89.0 to 91.8 mph. Because a pitch travels an average of 54 feet, four inches from the release point to the plate, an increase of 2.8 mph meant the ball arrived .0127 seconds sooner—a huge reduction in the hitter’s margin of error. Second, defensive shifts became mainstream. Players who had been taught to drive the ball up the middle saw repositioned infielders turn their grounders into outs.

In the summer of 2013, the down-to-the-ball swing wasn’t working for Martinez, then 26 and a mediocre .253 career hitter and .390 slugger. As he floundered, he marveled at the turnaround of Astros teammate Jason Castro. A .235 batter with little pop, he was blossoming into an All-Star catcher who would belt 18 home runs.

Then, watching the stroke of Brewers outfielder Ryan Braun, Martinez made a connection: It was the same as Castro’s. Their bats didn’t follow a steep path down to the ball; they were “on plane”—that is, mirroring the path of the pitch. Imagine the globe again: In the swings Martinez was watching, the barrel entered through the Southern Hemisphere and exited in the Northern.

“Who taught you that swing?” Martinez demanded from Castro, who gave him a name: Craig Wallenbrock.

One day after the season ended Martinez was in Santa Clarita, Calif., working with Wallenbrock and his assistant, Robert Van Scoyoc, spending five hours a day in the cage. Martinez wanted to know everything, and there was much to learn. Wallenbrock, a self-described “mediocre college baseball player,” dropped out of San Diego State in the 1960s because . . . well, it was the ’60s, and good times and the ocean beckoned. He returned to baseball some years later when his brother, 11 years younger, wanted help with his hitting. Wallenbrock simply began dissecting big league swings as much as he could. “There was nothing spectacular,” he said. “Just learning the hard way.”

Soon he began counseling others, and by the mid-1980s he had gained a reputation and a part-time scouting gig with the A’s. The business grew. Around 2000 he started working with a kid from Granada Hills High: Braun, who would set the school home run record as a senior with 25.

Wallenbrock says he admires Li because “his paintings didn’t have anything central or big to catch your eye. There was a lot of detail. You had to look at all the subtle nuances.” He felt the same way about hitting. It wasn’t about just one or two keys but all the links in a long kinetic chain—“an infinite number of fractions that need meticulous examination.”

Four meticulous months later Martinez was a changed hitter, though the Astros didn’t wait to see it; they released him in spring training. Since then his slugging percentage of .574 is second only to Mike Trout’s .579. Last season, despite missing a month with a sprained right foot, Martinez belted 45 home runs, the most ever without 500 plate appearances, after which he signed a five-year, $110 million contract with Boston.

Another Wallenbrock pupil, outfielder Raúl Ibañez, joined the Dodgers as a special assistant in 2016 and persuaded them to hire Wallenbrock as a consultant. After that season, while Los Angeles was in the playoffs, the club sent utility player Chris Taylor to work with Wallenbrock and Van Scoyoc in Glendale, Ariz. A career .234 hitter with one home run, Taylor rebuilt his swing, adding a pronounced trigger mechanism with his hands. Last year Taylor, 27, hit 21 home runs and slugged .496. This offseason, Bradley Zimmer of the Indians, Brandon Drury of the Yankees, and Juan Lagares and Tim Tebow of the Mets were among the many players to seek the Oracle of Santa Clarita and join the revolution.

***

The summer of Martinez’s epiphany, two third basemen began implementing similar—and ultimately wildly enriching—swing changes. Donaldson, a career .232 hitter with Oakland, began tearing up the AL after a winter under Bobby Tewksbary, who had played briefly (72 games) and poorly (.229) in the Can-Am independent league. In 2008, Tewksbary took a job as general manager of a physiotherapy clinic in his native New Hampshire, but his love of baseball and the gnawing mystery of why he failed as a hitter never left him.

Studying clips of the greats in 2009, he found one that changed his life: a side view of Albert Pujols in slo-mo. Tewksbary played it over and over, and solved the mystery.

“For my entire career, what I had been taught and what a majority of hitters had been taught, was that the back foot, back knee and hands all fire together,” Tewksbary says. “They move toward the pitch at the same time. When [Pujols’s] back knee went forward and his hands went up and back, it was a wow moment. The best hitter on the planet was doing what I thought was wrong. I had to shut down everything I knew about hitting and look at it as objectively as possible.”

That winter Tewksbary began to work with Chris Colabello, a former Can-Am teammate. By 2011, Colabello was the Independent League Player of the Year; two years later, he was on the Twins. Others, including Donaldson, noticed, especially as Tewksbary spread his gospel on his website. With his overhauled swing, Donaldson finished in the top eight in MVP voting for four straight years starting in 2013—and won it in ’15 as a Blue Jay, earning a two-year, $28.7 million deal.

Also in 2013, Turner, a career .260 utilityman with little power, became intrigued with the new swing of Marlon Byrd, his Mets teammate. Byrd told him he had learned it from Doug Latta, a former high school coach who never played pro ball and who operated two batting cages at an industrial park in Northridge, Calif.

By September, with no home runs on the season, Turner says he decided, “‘Screw it. I’m going to start hitting the way Marlon told me.’ I go into Cleveland and I hit a home run off [Cody] Allen. Two days later, off [Danny] Salazar, I hit another homer. We go back home, and I hit some ropes off the wall in centerfield. I was feeling really good.”

Turner hit .357 and slugged .571 in September. Never in his life had he raked like this. He spent the winter training with Byrd under Latta’s direction in Northridge. As Houston did with Martinez, the Mets didn’t wait for Turner’s swing to take root. They released him. Since then, he has hit .303 for L.A. and slugged .502, the best in franchise history by any third baseman with 500 games. In 2016 he re-signed for $64 million over four years.

“Before launch angle was a big deal,it was constant talk with Doug about getting the ball in the air,” Turner says. “I don’t think about east and west anymore. I think about north and south. I don’t care where it goes, as long as it goes up.”

***

In 2015, MLB rolled out Statcast, a torrent of data derived from tracking the movement of every ball and every player. Launch angle was the system’s breakout hit. Statistical analysts had known for two decades that balls hit in the air generate more production than balls hit on the ground, but launch angle made the data mainstream and fun. The replays, embellished by comet trails on flying baseballs, whooshing sound effects and a stream of esoteric statistics, spoke the language of a generation raised on video games. (It was in the second half of that season, when the homer rate jumped suddenly, that speculation began about a livelier baseball. MLB expects to release soon the results of research it conducted this winter on the ball’s properties.)

More important, the data expedited the acceptance of the modern swing. The average launch angle has increased every year since Statcast debuted: from 10.1 degrees to 10.8 to 11.0. It took a hundred years for baseball decision-makers to replace batting average with on-base percentage as the coin of the realm; it took less than a decade for them to replace OBP with slugging percentage. The object is to score runs, so it’s not just getting on base but where you get on base—i.e., closer to home via doubles, triples and, especially, dingers.

As defensive shifts proliferated, many speculated they would trigger an emphasis on opposite-field hitting. Instead the reverse has happened: To beat the shift, hitters have concentrated more on pulling the ball over it. Why? Opposite-field hitting yields singles (batting average). Fly balls to the pull side yield extra-base hits (slugging).

Last year players struck 41 balls at a 13-degree launch angle with at least 90 mph exit velocity. Every one of them was a hit—a 1.000 batting average. Sounds ideal, right? But those 41 hits comprised 37 singles, four doubles and no home runs. Double the launch angle to 26 degrees at 90-plus mph and you get the sweet spot for home runs: 469, the most at any angle.

The Cubs, the Brewers and the Giants were among teams last season that strung yellow ropes from home plate to the top of the cage to delineate the preferred launch angle range. San Francisco, for instance, set the low rope at 5 degrees and the high rope at 25. Last year players slugged .979 when they launched balls between those two marks, and .367 when they didn’t.

Most players, however, focus on the process of getting the ball airborne, not specific launch angles, which mostly are determined by the height and track of the pitch. “They’re fun to look at,” Gallo says, “but I don’t measure my swings off them.”

***

The converts keep coming. What Gallo was to the fly ball last season, first baseman Eric Hosmer was to the ground ball. No corner player hit more grounders than Hosmer, a trait that caused sabermetricians to question the Padres’ wisdom in handing him an eight-year, $144 million contract. Last year major leaguers batted .410 on balls in the air and .245 on balls on the ground.

But Hosmer began to get religion when it came to the modern swing after hitting .225 last April for the Royals with an average 2.1-degree launch angle. “I started breaking down hitters and what they do and changed my whole approach,” he recalls. “I had been swinging down and trying to drive through the baseball with backspin. So instead of the lead elbow going down, you kind of lock the lead elbow and work up and through the ball.”

From May on he raised his launch angle to a still-paltry 3.9 degrees; with the added loft he batted .335 and slugged a career-high .533. Changing a swing is hard work. “A huge deal,” says Indians first baseman Yonder Alonso, who before last season, in addition to physical training, worked four to five hours in the cage every day. “I basically didn’t see my family.” After never having hit more than nine home runs in a season, he smoked 28 at age 30.

Over the same winter Marisnick, an Astros outfielder and a .225 hitter with little power, sought out Eugene Bleecker, a hitting instructor in Riverside, Calif. Though Bleecker, 33, never played beyond Division II, Marisnick put his career in his hands upon the recommendation of Dodgers catcher Austin Barnes, a Bleecker protégé who had a breakout season in 2017. Barnes and Marisnick had been teammates at Riverside Poly High. Bleecker wouldn’t let Marisnick pick up a bat for a month. Instead, they used a PVC pipe to build new muscle memory.

“I was asking him to hit the ball in the air more, and he physically could not do it,” Bleecker says. “We were repatterning his movements. You have to look at motor learning and complex and dynamic systems. That’s what hitting is. You can’t teach mechanics.” With his remade stroke Marisnick hit a career-high 16 homers in little more than half a season while slugging .496.

Lofting the ball is a simple concept but requires an intricate and carefully timed kinetic chain. These are some of the key links to the modern swing:

•Get ready early Rather than beginning with the hands back and loaded, they work up and back, creating rhythm and barrel movement as the pitcher delivers. A leg kick is often added as a mechanism to help get started.

• Get in lag position early and slowly The back elbow drops independently, leaving the hands back and about shoulder height. As the elbow reaches toward the back hip, the barrel tilts behind the batter, toward the umpire’s shoulder, so it can get on plane with the pitch earlier.

•Get on plane as soon as possible The pitch travels on a decline of 6 to 12 degrees, so it’s important that the barrel get on that path far back in the zone. (Also: Hit through a path, not to a spot.)

•Hit the fastball deep in the zone The old method was to hit it out front. But that commitment left a batter vulnerable to off-speed pitches—the barrel was gone before the off-speed pitch got there. By committing to hitting fastballs deep—an opposite-field gap orientation, which is how Trout thinks—a hitter who keeps his barrel on plane with the pitch can adjust to off-speed pitches. This is the margin of error hitters talk about; the barrel is on plane longer. It describes how Tigers slugger Miguel Cabrera hits: fastballs the other way, off-speed pitches pulled.

•Hit the bottom third of the ball on a slight upswing “When you’re coming up and through the ball it gives your barrel that much more of the ball to work through,” Hosmer explains. To generate lift, Kris Bryant says, instead of “taking the knob to the ball”—the old method—he thinks about “taking the knob to the hitter’s eye [the dark background above the centerfield wall]. Get your hands up high.”

***

A minor league player, whom Dodgers president of baseball operations Andrew Friedman prefers to leave nameless, walked into camp last year with a new swing. He drastically dipped his back shoulder and took a vicious uppercut, producing mostly would-be pop-ups to the top of the cage.

“What are you doing?” a coach asked.

“Hitting the ball in the air.”

This is the disclaimer portion of this story. The chase for the modern swing holds the same downside as pitchers’ pursuit of velocity, which can damage young arms and set back careers. You can find poor imitations of Donaldson’s swing everywhere in amateur baseball.

“We watch these videos and see a lot of kids are dipping their shoulder trying to hit the ball straight in the air,” Gallo says. “For us, that’s not the way you do it. We send each other videos like, ‘Man, they’re going to ruin this generation, because [these kids] are not going to hit 95 [mph] with movement.’ You kind of feel bad for them.”

Pitchers already are adjusting to the modern swing by throwing more high fastballs, which are difficult to get on plane and launch. Last year hitters batted .321 on four-seam fastballs over the width of the plate, belt high and below. They hit .240 when pitchers elevated those fastballs to the top third of the zone or above.

The modern swing is not for everyone. Nobody wants a speedster like Billy Hamilton to hit the ball in the air. And some players simply don’t have the fast-twitch movements to execute the kinetic chain. According to a major league source, Toronto was concerned that Donaldson’s enthusiasm for the swing may have caused teammates to adopt it. In 2016 shortstop Troy Tulowitzki raised his launch angle to 14º and hit fly balls at a career-high rate—while finishing with the worst on-base percentage in any of his nine qualified seasons. Last year, in limited time, he lowered his launch angle to 9.5 degrees and hit a career-high rate of grounders. “Donaldson is hypermobile,” says Bleecker. “He thinks about his stretch like he’s unwinding a tornado. Not everybody can do it like that.”

The revolution also has scrubbed much nuance out of the game. One out of every 2.98 plate appearances last year ended in a home run, strikeout or walk—none of which require defense—the highest such rate ever. Stolen base attempts were at their lowest rate in half a century. Sacrifice bunts dropped to an all-time low for the third season in a row. Strikeouts were at a record high for the 10th straight year. Singles reached an all-time low (63.7% of hits).

“It’s such a power game now,” Tewksbary says. “In some ways it’s bittersweet. I enjoy the mental game and home runs. It’s exciting but at the same time it’s boring. When you scale it down to the high school level and see pop-ups that don’t go out because these kids are chasing home runs, it does take away from the game.”

***

Here’s another sign of the revolution: Major league organizations are putting people in uniform who never played affiliated baseball. The Diamondbacks hired Van Scoyoc, 30, whose playing days topped out at a California community college, and gave him the newly minted title of hitting strategist. He’s an adjunct to Dave Magadan, who played 16 years in the majors and has been a hitting coach for 15.

“Almost like a hitter, as a coach you can’t think, I’m good. I can’t get any better,” Magadan says. “You have to be open and not have so much ego. As a player I was the opposite of what guys are taught today. It was all ‘direct to the ball.’ If I had known how to get the ball in the air to the pull side ... it makes you nostalgic for what could have been.”

Houston brought in Jeff Albert, 37, as an assistant hitting coach. After playing 11 games of independent ball, he got a master’s degree in exercise science at Louisiana Tech, ran a website dedicated to baseball training and analysis, and coached nine years in the minors. The Mariners brought in minor league hitting coordinator Hugh Quattlebaum, 39, an Amherst graduate and four-year minor leaguer who was running an online training site, giving private lessons and coaching travel ball.

“Technology and data are the great equalizers,” Seattle GM Jerry DiPoto says. “Can you imagine the day when an exercise physiologist and a biomechanics specialist walk into the manager’s office and say, ‘These three guys can’t play today because their energy is low’ and the manager says, ‘O.K.’? That day already is here.”

Hank Haney, Butch Harmon and David Leadbetter, three of the most renowned golf swing coaches, won one combined PGA event. Baseball is embracing the same type of swing coach—teachers from outside the ropes who, with an Internet connection, have studied hitting movements in the finest details. The Mariners hired a quality assurance coach, Dustin Lind, 29, who played club baseball at Idaho State, became a physical therapist and has so thoroughly studied hitting that he filled a 15-gigabyte Google drive with thousands of videos, articles and documents and posted it on Twitter. A clip of Donaldson on MLB Network explaining his swing has been viewed more than 750,000 times.

“Video is a game changer,” Tewksbary says. “Twitter lights up every time there’s a home run and a slow-motion replay of the swing. It didn’t happen this quickly in the past. It’s all about information. I worked really hard to make my swing work, with access to video and all these metrics. The direction it’s really going is how to optimize the performance from the mental side. The physical side is not a secret any more. Take a good swing, hit the ball in the air, and you have a chance to perform well.”

****

As Richards pulled the ball out of his glove and behind his back, Gallo began to move his hands. Gallo, like Bryant, waits with the bat held parallel to the ground, so that as the pitcher begins his delivery he already is creating rhythm and movement by having to raise the barrel. As this happens, Gallo also starts his leg kick. Getting ready early, with movement, has been a key for Gallo since rookie ball, in 2012, when he began working with Justin Mashore, now the Rangers’ assistant hitting coach.

Gallo took his stride, lifted his back elbow and then dropped it into its “slot” behind his left hip as his hands loaded. It is the same trigger to a swing change that Dodgers first baseman Cody Bellinger learned in 2015, when after hitting four home runs in two years he suddenly crushed 30 in Class A. Last season Bellinger set an NL-rookie record with 39 homers. One of Bellinger’s swing tutors in ’15 was Damon Mashore, Justin’s brother.

“The hitch is a big key for me,” says Bellinger, using a word that traditionally was viewed as a negative, even though many great hitters, including Ruth, Williams, Hank Aaron, Willie Mays and Barry Bonds created this early movement with their hands.

Richards’s heater is typically 96 mph and tops out at 99. Gallo dropped his barrel into the plane of the pitch in time to hit Richards’s best fastball deep in the zone. Instead, Richards spun a 89.5 mph slider. Had Gallo “cheated” to hit Richards’s best fastball out front, his barrel would have passed through the zone before the slower pitch arrived. But because he got ready early and intended to hit the fastball deep, Gallo’s barrel remained in the path of the pitch.

“Right off you can see, ‘Oh, my God, that’s backspun to center,’ ” Gallo recalls. “It feels amazing because you don’t even feel it off the bat. It’s the greatest feeling in the world. You know you hit it, but you don’t feel it.”

The ball sizzled off his bat at 116.2 mph with a launch angle of 26 degrees, the sweet spot for homers, landing at the top of the hill in centerfield at Angel Stadium. It bounced three times on the green turf before rolling down, like the ball in a giant pachinko game. By the time it hit one of the boulders on the bottom of the hill, Gallo had touched third base. Just put it in play? There were 44,424 balls hit last season on two-strike counts. This went the farthest of them all: 490 feet.

Bleecker likes to frame his students’ quest as a math problem. A hitter who gets 600 plate appearances in a year will see about 2,300 pitches and swing about 1,100 times. Twenty doubles and 20 home runs make for a solid season. One hundred players did so in 2017—the most ever.

But only 17 players reached 30 doubles and 30 home runs. “With just 60 good swings out of a thousand,” he says, “you’re worth $100 million. So the question is, ‘How can I get 10 better swings out of a thousand next year? Fifteen better swings?’ ”

The answer is undeniable. It is in the data. It is in the video. It is in the air. And it is in Mike Bryant’s indoor batting cage, where Kris still hits every winter and his dad gives private lessons. Every once in a while, when Kris is done, he will linger long enough outside the room to know the revolution is here to stay.

“I see all these eight-year-olds hitting the ball up into the top of the net,” Kris says. “It’s beautiful.”