For the past decade or so, baseball has played in what we could call the "information era." It began in earnest with the widespread installation of PITCHf/x pitch-tracking technology in 2008. As fans and writers, we've been able to learn a lot about many areas, from the evolving strike zone to pitch-framing to ideal launch angles.
But, of course, the granular information isn't consumed or analyzed only by those outside the game. Information has also been consumed by the players and teams, so certain effects shouldn't be surprising. Pitchers, for example, are more aware of documented hitter weaknesses. And hitters, in turn, are more aware of their own vulnerabilities.
PITCHf/x has been measuring pitches, and the similar HITf/x has been measuring batted balls. More recently, Statcast has entered the mix as a major data source, bringing more information than ever to the table. The Pirates have pointed to the numbers to try to get their hitters to put more balls in the air. Daniel Murphy has pointed to the numbers to try to get Ryan Zimmerman to put more balls in the air. So much data is now available that potential shortcomings can be more quickly identified and addressed.
I've talked to a number of baseball people, and there's a certain shared feeling that now, more than ever before, players are making sudden changes to their approaches.
Many people know about, say, J.D. Martinez and Josh Donaldson and Justin Turner, who decided to try to hit more fly balls. They were responding to data presented to them. They're not alone. Hitters especially are identifying weaknesses and trying to tweak them away, following a few pre-Statcast years of pitchers arguably having the information advantage. Many hitters are swinging at different pitches. Many are just plain swinging differently. The "information era" is now helping to teach hitters how they can defend against good pitching.
As such, many recent articles have been written about hitters who've consciously changed. In a sense, it has become a new genre of analysis. Analysts are able to go into the greatest-ever level of detail. Naturally, changing habits works better for some players than it does for others. You tend to hear more about the success stories. In this article, we'll highlight five hitters who've changed for the better and five hitters who've fallen off a bit.
Let's start with the positive changes.
Five on the rise
Yonder Alonso
Numbers to know: 12 and 20
Stats to know: Homers and ground ball rate
Hitters are supposed to peak in their mid-20s to late 20s, right? Yet here's Alonso, breaking out at age 30. This one is so simple that in a way it's shocking it took this long. Alonso was drafted No. 7 overall in 2008 by the Cincinnati Reds. He has had nearly 2,500 plate appearances in his eight season in the majors. He has been on the radar for a while, but he has been about as average as a regular first baseman can be, with a 7.0 WAR, including 1.3 WAR in 2017.
In 2015 and 2016 combined, Alonso hit 12 home runs. Already this year, he has hit 12 home runs. Back in spring training, Alonso talked about a desire to get more air under the ball.
Alonso has trimmed his ground ball rate by 20 percentage points. Among the 197 players who have batted at least 100 times in each of the past two seasons, Alonso's drop is the biggest; no one else is within seven points. In short, Alonso is trying to elevate, and he has found power he has always had. Although it has meant a few extra strikeouts, there's nothing better a hitter can do than go deep.
Francisco Lindor
Numbers to know: 11 and .551
Stats to know: Ground ball rate and slugging percentage
Lindor has cut his ground ball rate by 11 points, more than all but five players. Lindor also is pulling the ball more than ever, and from both sides. You'd think it might be difficult for a switch-hitter to make significant changes, but Lindor has pulled it off, and his slugging percentage has jumped more than 100 points, from .435 in 2016 to .543 through Tuesday's games in 2017.
The knock on Lindor was that he didn't profile as a power hitter. With nine homers this year, he's already more than halfway to last season's home run total of 15. Lindor doesn't hit like Aaron Judge, but you don't need to in order to benefit from hitting the ball in the air more often.
Brett Gardner
Numbers to know: 32 and .521
Stats to know: Fly ball rate and slugging
The Gardner story is much the same as the Lindor story: more batted balls in the air, leading to more damage. What separates Gardner from Alonso and Lindor is that Gardner is doing something he has done before. A few years ago, he started hitting more balls in the air, chopping 10 points off his ground ball rate. That went away last season, and the grounder rate returned to 52 percent. But Gardner has bounced back, and then some. Only seven players have more substantially reduced their ground ball rates. And the left-handed-hitting Gardner, at the same time, has hit the ball far more often toward right field.
Throw in the fact that Gardner is swinging less often than he has since 2010, with a swing rate of just 32 percent, and you have the profile of a selective hitter. Of his seven home runs, five have come at Yankee Stadium, suggesting it's a particularly comfortable environment. Gardner's approach might not work for the average team, but in that ballpark, even he can be rewarded for pulling a few extra flies and liners. And so we reckon with a Brett Gardner who's slugging .521.
Aaron Hicks
Numbers to know: 190, 13, 21 and 16
Stats to know: wRC+ and swing rate
Hicks owns a wRC+ of 190, which means he has been 90 percent better than a league-average bat. That ranks him seventh in all of baseball and second on the Yankees. Last year, he was 34 percent worse than a league-average bat. What's going on? The secret here isn't more fly balls. Hicks hasn't been a part of that trend. For Hicks, it's all about pitch selection. Hicks has always had a pretty good eye, and now he's delivering on his old promise.
Hicks' swing rate has come down by 13 percentage points. That's baseball's biggest drop. And no hitter in either league has swung less often at pitches out of the strike zone. For Hicks, it's not about swinging less; he's spitting on pitches down, while increasingly going after pitches up. Productivity has followed, and although Hicks isn't this good, there's not much bad you can say about a guy who has more walks (21) than strikeouts (16) through May 16.
Michael Conforto
Numbers to know: 17, 70 and 30
Stats to know: Pull rate and ground-ball rate
Let's stay in New York. Conforto isn't hitting a lot more fly balls. He already has a fly ball-oriented swing, and his actual swing and contact rates haven't budged much. The key for Conforto has been making the most of what's more of an all-fields approach. Using that same sample of 197 players from the past two seasons, no one has seen a bigger drop in balls hit to the pull side than Conforto, whose pull rate is down 17 percentage points, from 43 percent. He has one of baseball's lowest pull rates, a la Joe Mauer.
The change is biggest if you look at Conforto's grounders. It used to be that about 70 percent of his grounders were pulled. This year, he's at just 30 percent, which is a reflection of the left-handed-hitting Conforto trying to stay up the middle. It gives him a greater margin for error. When he's ahead by a little, the ball goes toward right field. When he's behind by a little, the ball goes toward left.
Five on the slide
Alcides Escobar
Numbers to know: .252, 0, 28
Stats to know: Slugging percentage, homers and strikeouts
If there has been one lesson from the fly ball trend, it's that even under-powered hitters can find success in the air. No one would argue that Brian Dozier's raw power is among the league's elite. But there has to be a cutoff somewhere, and maybe Escobar is that cutoff. He has baseball's third-biggest drop in ground ball rate. Yet Escobar is slugging .252 through May 16. He has hit far more balls in the air than ever, but he doesn't have enough pop to justify doing so. To make matters worse, the approach has also increased Escobar's strikeouts (28). So he has lost some of his main offensive skill -- making contact.
Escobar has zero home runs. In his career, he has topped out at seven. I understand several Royals might be feeling the pressure to produce, but Escobar is the last guy you'd want to overswing. So far it has produced a 23 wRC+, meaning he has been 77 percent worse than an average hitter.
Curtis Granderson
Numbers to know: 26, 8, 30, 9 and 2
Stats to know: wRC+
Escobar's wRC+ is awful, but Granderson's wRC+ of 26 isn't much better. The difference here is that Escobar has never been very good offensively. Granderson was good as recently as last season, and his tumble has been partly responsible for the Mets' middling start.
A year ago, Granderson had eight popups and 30 homers. This year, he has nine popups and two homers. His swing has been off, perhaps because his approach has been off. Granderson has nearly doubled his rate of swings at the first pitch, from 9 percent to 16, and his overall swing rate has gone up 8 percentage points, which is baseball's second-biggest increase. Granderson has made an effort to be more aggressive, but there has been no thump to back it up. As a result, he's just making more outs, and sooner.
Albert Pujols
Numbers to know: 60 and 50
Stats to know: Pull rate
I hesitate to claim that Pujols has made a decision to change. He's a Hall of Fame hitter and deserves the benefit of the doubt when it comes to his decision-making. So perhaps Pujols has had his profile changed for him. He has become more aggressive and more pull-oriented. Although he's seeing a career-low rate of pitches in the zone (44 percent), he's swinging at a career-high rate of pitches out of the zone (37 percent). And Pujols is also pulling the ball nearly 60 percent of the time. For his career, he has come in under 50 percent.
Pujols can't run out ground balls, yet he's hitting too many of those (49 percent), a consequence of focusing on one side of the field. Pujols was once an elite hitter, but he isn't able to hit at that level as often.
Trevor Story
Numbers to know: 21 and 15
Stats to know: Fly ball rate and wRC+
The thing that was so strange about Story coming up in the minors was how he blended strikeouts with a ton of fly balls. That same approach carried over into the majors in an impressive rookie campaign. Now in his second season, Story has been hitting even more fly balls. It's fair to wonder if he has simply gotten too extreme, with just one of every five batted balls (21 percent) staying on the ground. Story's wRC+ has been cut nearly in half. His strikeout rate is also up, because he has swung under too many pitches.
For a while, the uppercut worked. And, who knows, it could work again, even as it has grown more extreme. But it's possible that Story in 2016 was near the limit of how extreme one can reasonably be. The more you try to hit the ball in the air, the more likely you are to whiff and pop out. Story is doing those two more while going deep less. Whereas 24 percent of his flies wound up as homers last year, this year he's down to 15 percent. He could have to turn things down a notch or two if he wants to tap into that rookie-year magic.
Aledmys Diaz
Numbers to know: 4 and 36
Stats to know: Walks and swing rate
As a rookie in 2016, Diaz hit for power, but his real strength was drawing a fair number of walks (41) and seldom striking out (60 in 460 plate appearances).
This year, Diaz is still making contact, but he has walked just four times in 34 games and 150 plate appearances through May 16. He's going after the first pitch more often, and he's also expanding out of the zone more often. Whereas Diaz last year chased would-be balls 26 percent of the time, this year he's at 36 percent. The discipline hasn't been there, and the Cardinals have entrusted him mostly near the top of the order.
It makes sense that pitchers might try to challenge Diaz, but he has the pop to punish them. He just has to stay more composed, swinging with more restraint. Diaz, at his best, is more patient than aggressive. We're waiting to see that Diaz for an extended stretch in 2017.