The Most-Changed Hitters of the Young Season
We spend so much of our time talking about players making changes. One could argue, too much of our time. I get it! The stories can blend together. But the analysis we’re capable of now is so much better than it used to be. The public tools and information have opened doors we never could’ve dreamed of. So all the different insights have shaped the way people on the outside cover the game on the field. One thing we understand better than ever is how players might forever evolve.
Changes everywhere. Which hitters have made changes? Taylor Motter has made changes. Miguel Sano? He’s made changes. Travis Shaw, Elvis Andrus, Xander Bogaerts — they’re all making changes. I wanted to take a step away from focusing on any given individual in particular. Which hitters seem the most changed, compared to 2017? I assembled a spreadsheet. There’s a table below, with 10 names. Let me explain this real quick.
I decided to focus on four traits that I think reflect a hitter’s profile. Those four traits: swing rate and contact rate (from FanGraphs), and average exit velocity and launch angle (from Baseball Savant). A hitter is mostly, if not entirely, how often he swings, and what happens after he swings. I gathered all four data points for hitters who played in both 2016 and 2017. So I guess that makes it eight data points. For each data point for each year for each hitter, I figured out the standard deviations above or below the league average. Then I calculated the absolute value of the change in standard deviations between 2016 and 2017. I wound up with four absolute values, for every hitter. I added them up to yield what I’ll call the “Change Index.” The larger the number, the more changed the hitter.
That was an unpleasant paragraph. Here’s the fun part! Behold, the changed hitters! I set arbitrary minimums of 75 plate appearances in each season. Don’t complain about that, please, because I don’t care.
| Player | Change, Swing% | Change, Contact% | Change, EV | Change, LA | Change Index |
|---|---|---|---|---|---|
| Mike Moustakas | 10% | -9% | -5 | 7 | 6.5 |
| Aaron Judge | -6% | 11% | 0 | -10 | 5.5 |
| Khris Davis | -12% | 3% | 4 | -4 | 4.8 |
| Trevor Story | -4% | -10% | -1 | 16 | 4.8 |
| Alex Gordon | 3% | 9% | -3 | -10 | 4.6 |
| Randal Grichuk | -2% | 0% | -7 | -9 | 4.6 |
| Wil Myers | 10% | -6% | 2 | 3 | 4.5 |
| J.J. Hardy | 8% | -7% | -2 | 4 | 4.3 |
| Mitch Haniger | -5% | 5% | -7 | -4 | 4.3 |
| Yonder Alonso | -3% | -9% | 1 | 10 | 4.3 |
Compared to last year, the most-changed hitter in baseball is Mike Moustakas. In fact, it’s Moustakas by a healthy margin. Now, Moustakas had his own 2016 season cut short by injury, but as we see him now, he’s swinging a lot more, and he’s making a lot less contact. While his exit velocity is down, his launch angle is up, and Moustakas has focused on pulling the ball for power. Maybe he’s felt some pressure, getting so little support from the rest of the lineup around him.
Moustakas will be a name to watch. Unsurprisingly, Aaron Judge makes it in here, thanks in large part to his dramatic contact-rate improvement. He’s also cut down on his launch angle, and although we normally associate launch-angle increases with power, Judge has more of that flat Giancarlo Stanton attack path. Don’t complain while it’s working.
There are a couple A’s on here — one who’s always hit for power, and one who’s learning. What I think I love about Trevor Story here is that he already had an extreme launch angle, and now he’s practically Schimpf-ing. Not that Story should want to keep this up; 2017 has not been a success. You can turn it up to 11, but don’t turn it up to 12. Things get broken at 12.
That’s where I’ll leave it for now. Remember that most-changed doesn’t automatically mean most-changed for the better. Consider, say, Story, or Alex Gordon. Changes are changes. Just because we often focus on the successful adjustments doesn’t mean there aren’t always bad things happening, too.
