It is possible, of course, that this power boom is caused by chemicals. But that would mean a widespread wave of cheating is taking place despite increasingly stringent drug testing. Many pitchers believe the ball is harder than usual, with lower seams, though Major League Baseball insists that all testing shows the balls to meet normal specifications.
More plausible, perhaps, is that the homers are an outgrowth of baseball’s statistical revolution and the logical concepts it has popularized. Hitters understand that driving the ball in the air, instead of on the ground, offers far more potential for production and financial reward. Technology shows them precisely how to angle their bats to turn fly balls into homers, and many have the skills to apply what they know.
“We’re allowing analytics people to come in, and for years baseball people didn’t like analytics people; they were a bunch of nerds,” said Craig Wallenbrock, a longtime hitting trainer and a former scout who consults for the Los Angeles Dodgers. “That may or may not be true, but that has nothing to do with what they’re measuring. They’re looking at launch angle, exit velocity, working with actual facts about what happens. It hasn’t changed the way we hit a baseball, but it’s changed our understanding of what’s going on.”
The pace of the adjustments has been sudden, with the home run spike beginning in the summer of 2015, the year that began the so-called Statcast Era, when baseball began measuring — and publicly emphasizing — the DNA within every ball in flight: the rate of spin for each pitch, the angle of the hitter’s bat upon contact, the speed at which every batted ball travels.
For the best hitters in the world, more data means a more precise road map from bat to bleachers. And while the proportion of ground balls has essentially held steady — 44.3 percent to 45.3 percent for each year of this decade, according to FanGraphs — hitters seem to know how to drive fly balls with more backspin to make them into homers. The percentage of fly balls that become homers has risen in each of the last four years, from 9.5 percent in 2014 to 13.7 percent this season.
The rapid evolution does not surprise Billy Eppler, the Los Angeles Angels’ general manager.
“It doesn’t, because of something that, actually, Alex Rodriguez told me some years back: ‘If you can articulate what you value, and what you’re looking for, players of this caliber of athleticism can turn themselves into it,’” said Eppler, a former Yankees assistant. “It’s kind of standing the test of time, where guys know that runs are valuable, and the ones that have the capability to do it — meaning the strength — are lifting the ball a little bit more and putting more balls in the seats. But the trade-off that comes with that is contact.”
That’s because the emphasis on home runs creates more holes in hitters’ swings and pitchers are well equipped to exploit them. The most extreme case, perhaps, is San Diego’s Ryan Schimpf, who had 14 homers, and just 12 other hits, to go with 70 strikeouts before his demotion last month.
Strikeout rates have risen every year for a decade; this year, the average total of strikeouts per game is 16.489, up from last year’s record of 16.055. The average fastball velocity has risen each year since 2008, according to FanGraphs, and is now up to 93.6 miles per hour, as starters go fewer and fewer innings and teams turn to more and more hard-throwing relievers to fill the rest of the game. All of them are being encouraged to be more aggressive, which also becomes a factor in the home run surge.
“What has happened is, because of the increase in velocities, you’re seeing more pitchers pitching up — more pitching coaches and organizations encouraging pitches thrown up at the top of the zone — where that was never the case before,” said Colorado Rockies Manager Bud Black, who pitched in the majors from 1981 to 1995. “My generation was down, down, down and away, and if there was a guy who would chase a high fastball, you would throw it up. But you never made it part of your game.”
That can lead to more strikeouts, but also more mistakes that get hammered. Jon Lester, the veteran left-hander for the Chicago Cubs, added that umpires also seemed to be calling fewer strikes on low pitches this year.
“You’ve got to bring that ball up just a little bit, giving them a better opportunity to hit the ball,” Lester said.
One hitter who takes advantage is Lester’s teammate, third baseman Kris Bryant, the National League rookie of the year in 2015 and the most valuable player last year. Bryant’s father, Mike, was a minor leaguer for the Boston Red Sox and learned hitting from Ted Williams. Mike Bryant now instructs young hitters in Las Vegas, and helped mold Kris into a prodigious — and unapologetic — fly-ball machine.
“Keep it really simple: Hit it hard, hit it in the air,” Mike Bryant said. “We want them to swing aggressively, we want them to make a big move forward into the ball, transfer their weight forward. Swing up, don’t chop down. Barrel below the hands at contact, not above. ‘Don’t hit the top of the ball, don’t throw your hands, don’t stay back’ — all the phrases that you’ve heard for years and years are totally the wrong things to teach.”
He said strikeouts were up because the pitchers were better, not because hitters had changed. Actually, he said, hitters have not changed as much as they have learned how to use launch angles to their advantage. Greats of the past like Williams and Mel Ott, Bryant said, may have done so intuitively.
Ott, the third player to reach 500 homers — after Babe Ruth and Jimmie Foxx — would practice lofting fly balls down the short right-field line at the Polo Grounds, to hook home runs inside the foul pole. Playing for the New York Giants from 1926 to 1947, he led the National League 10 times in at-bats per homer, succeeding with an unorthodox style.
“You go back to Mel Ott, look at the way he held the bat,” Mike Bryant said. “Why did he point the bat straight back at the catcher? Do you think he just did that to be different? No, he did that with purpose. He pointed the bat straight back at the catcher because he wanted to start with his hands low and finish high, or at his shoulders, because he thought, ‘How am I gonna hit this pitch?’ He wanted the swing plane to be up because they had a high mound and they were pitching downhill. These guys were thinkers. Everybody’s been telling you for generations not to think too much. You have to think.”
Today, the thinking hitter wants to know the reason for an outcome, and he knows data will provide an answer. Batters this season have a .252 batting average on fly balls and a .241 mark on ground balls, many of which are gobbled up by over-shifted infielders. The gap in slugging percentages is much more striking: .751 on fly balls, .261 on grounders, according to FanGraphs. Understandably, hitters are less likely than ever to accept the wisdom that prevailed not long ago.
“Go back a decade and almost every hitting coach was telling you to hit the ball hard on the ground, hard on top,” said San Diego Padres Manager Andy Green, a utility player in the majors from 2004 to 2009. “That’s just not the vernacular of the game today.”
A record 111 major leaguers bashed at least 20 home runs last season, making power almost a job requirement for a spot in the lineup. Accordingly, more and more players — Josh Donaldson, J. D. Martinez, Daniel Murphy, Justin Turner — have tailored their swings to change their style of hitting, often through an intense off-season overhaul with a private coach.