The History of the Adjustment to Mike Trout

Back in last year’s playoffs — we’re going to think for a minute about last year’s playoffs — Mike Trout hit a big home run off James Shields. The pitch was a fastball, pretty high and pretty far inside, and though there’s nothing immediately unusual about Mike Trout hitting a dinger, that particular brand of dinger was unexpected. The pitch, to that point, had been a weakness for Trout. An increasingly-exploited weakness. You remember — we wrote about it like a thousand times. The Mike Trout scouting report started going around in April or May, and from there it never really corrected itself.

You’ll recognize this image, or at least something kind of like this image. Trout’s run-value heat map for 2014, from his player page:

The best player in baseball. Seemingly the most obvious Achilles’ heel in baseball. Who wouldn’t be fascinated? And, if you were a pitcher, why not try to adjust, if for no other reason than just to see? There were adjustments, indeed.

Using the tools at Baseball Savant, I selected fastballs, then I set a pitch-height minimum of 2.5 feet off the ground. This worked as my definition of high fastballs. Last season, Trout saw about 35% high fastballs, which was the highest rate in baseball among everyone who saw at least a thousand pitches. Trout also had baseball’s highest rate of two-strike fastballs seen, be they high or not high. Relative to 2013, Trout’s high-fastball rate climbed by 6.1 percentage points. This was the greatest increase in baseball, by 33%. That’s the adjustment that was made. Pitch frequencies should fluctuate around some sort of optimal equilibrium, so what’s indicated is that Trout did become especially vulnerable to high heat.

The trend steadily increased, too. I think I’ve posted this table before, but, 2014 high-fastball rates for Trout, by month:

Month	High Fastball%
April	26.1%
May	32.5%
June	32.9%
July	38.1%
August	39.9%
September/October	40.3%

Every number is bigger than the previous number. Trout’s high-fastball rate was up in May and June, relative to the season before, but then it skyrocketed further. It was only being attacked more and more often.

But let’s think about that overall increase of 6.1 percentage points, year to year. I wanted to look for any kind of precedent, during the PITCHf/x era. So I looked for batters who saw at least 1,000 pitches in consecutive seasons, and then I isolated high-fastball-rate increases of five percentage points or more. The result? A sample of 19. But, curiously, a sample of 19, with 12 of those covering 2008 – 2009, suggesting there were maybe some inaccuracies with the 2008 data. Or maybe suggesting something else. It’s just a weird thing to notice.

What such a fastball-rate increase implies is a weakness against high fastballs. I wanted to know how the players responded. In the first year, they averaged about 26% high fastballs. In the next year, they averaged just over 32%, for an increase of 6.2 percentage points. In the year following, they averaged just under 31% high fastballs, for a decrease of 1.8 percentage points.

Yet different players in the sample went different ways. Which is what happens, in samples. And few of the players make for convincing comparisons to someone as talented as Mike Trout. For example, Kevin Millar saw a lot more high fastballs in 2009 than he did in 2008. Then he retired. We’ve got late-career Bill Hall. We’ve got later-career Ken Griffey Jr. There’s an aging Todd Helton, and Wilson Betemit, and the version of Melky Cabrera who tried to play through a tumor pressing against his spine. The kind of increase Trout saw overall isn’t unprecedented, but he’s more skilled than almost all of these players. I assume Trout has a better chance of adjusting than, say, 2009 – 2010 Rod Barajas.

There’s one particularly interesting name: Troy Tulowitzki. In 2008, he saw just under 26% high fastballs. The next year, he cleared 31%, then he dropped back down to below 29%. We’ve remarked before that Tulowitzki is kind of a version of Mike Trout with injury problems. From Brooks Baseball, here’s how Tulowitzki was pitched over the three years:

The adjustment pitchers made to Tulowitzki in 2009 reversed itself in 2010. It’s suggested that, in 2009, opponents believed Tulowitzki was most vulnerable against pitches up or inside. Tulo slugged .552. The next season, pitchers changed up again. Tulo slugged .568. He adjusted successfully to attacks on perceived weaknesses, and he remains to this day one of the three most talented players in the game. Though Tulowitzki saw a strikeout hike in 2009, he brought the numbers down the next year.

For the sake of reference, here’s how pitchers changed their approach to Trout between 2013 – 2014:

The important question is how Trout will adjust. He knows how pitchers have pitched him. He knows he’s best as a low-ball hitter. His physical ability is almost unparalleled, and he’s not yet even 24 years old. What happened last year was that pitchers tried to exploit the hole in Trout’s plate coverage, but now Trout has a whole extra year of experience, and a whole extra offseason of planning for the season ahead. It should also be recognize that Trout didn’t have so extreme a weakness before. Pitchers certainly didn’t pitch him like he did. Here’s Trout’s run-value heat map for 2012 – 2013:

It’s not good, up high in the zone, but compare that to a couple of awesome players.

Mike Trout, before, wasn’t so vulnerable against high heat. He became, or at least looked to have become, more vulnerable. Maybe this was because of a deliberate change in swing or approach, but Trout can make changes again if he wants, and he’s been better against these pitches in the past. It seems like Trout should be able to improve on this. The best players in baseball tend to be pretty good about shoring up weaknesses.

But for one thing, how motivated should Trout be to address this, anyway? From July on — when pitchers were most aggressively pitching Trout up — he posted a 147 wRC+, slugging .517. He remained an outstanding baseball player, albeit a baseball player with a strikeout rate of very nearly 30%. Things never quite reached a critical stage. Trout remains more like Mike Trout than any other player in the world.

And on the other hand, there’s the matter of few precedents. Already, there weren’t many players who saw high-fastball-rate increases of at least five percentage points season to season. Trout, between 2013 and 2014, gained more than six percentage points, but he gained something like twelve percentage points if you just compare 2013 to the second half of 2014. It was an extreme adjustment that pitchers made, unlike any other we’ve recently seen. Maybe some of this has to do with the fact that there’s more information out there than ever, so perhaps we’ll start to see adjustments made quicker. But pitchers didn’t just pitch Trout up more — they pitched him up a lot more, and the rate kept on increasing, suggesting that Trout didn’t get better about those pitches over the course of 2014.

Which is why 2015 should be so telling. Where we left off, the best player in baseball had a weakness that everyone knew about. The Royals attacked him up and in over and over and over, and Trout’s one home run was his only hit of the series. It feels like Mike Trout should be able to do something to counter the way he was attacked. He’s better than anyone else, and he’s more familiar with his weaknesses than anyone else. But we can’t say yet how much Trout’s pitch patterns are going to change. The way he’s pitched is going to tell you the way pitchers think he can be retired, and Trout will have to make them change what they were doing if he wants to strike out less often. We haven’t seen anything quite like this before, but perhaps that’s appropriate for one of the very best young players in the whole history of the sport.