Matt Carpenter and the Slider of Doom

Growing up, I was never a fan of deus ex machina in stories. I like coherent plots, and I like seeing how things early in a story set up what happens at the end. The hand of god sweeping down and suddenly fixing things for everyone isn’t my idea of a tidy narrative, and always struck me as a little lazy (maybe not the original Greeks, who used a literal crane to pluck characters off the stage, but the term as it’s used today). That said, this article is essentially deus ex machina in my own life, and wow is it sweet when it happens to you.

Let’s set the stage. Tuesday morning, New York City. It’s eight in the morning, and I’m headed to a car rental pickup. What a dope, you might say. Who drives in New York at rush hour? Well, me, that’s who. It’s the start of a wild two-day adventure for me; more precisely, it’s the last two days of a six-day whirlwind. Friday I flew back to New York for a friend’s wedding. Saturday was the rehearsal, Sunday the wedding, and Monday was spent packing up an apartment.

Now it’s Tuesday, and we’re on the road to Washington, D.C. Sweet, you might say. The Cardinals are playing there tonight! Not so fast, my friend. My wife and I are headed down to drop off some beloved but not currently needed stuff at my mom’s house. Then we’re turning right around and heading back to New York to catch an early-morning flight to San Francisco. Moving can be hard!

Why a 250-word introduction that only barely touches on baseball? Am I turning into Aaron? No, it’s all in service of Matt Carpenter. You see, I was fretting about what I’d write this week. With most of the week devoted to worldly concerns, a few FanGraphs articles in the hopper, and a game story to write on Friday, I had for real no idea what was going to run this space today. Then, like magic, an email appeared. A story idea, right to my inbox. Deus ex machina.

Wait a dang second. Is this real life? People just send me stories? Well, basically no. I do a lot of brainstorming on my own, and I’ve worked with other VEB writers to come up with ideas once or twice (Andrew St. John and I did companion pieces on Paul Goldschmidt at one point). Sometimes my wife comes up with something she finds interesting about baseball and I turn it into a story. Still, though. Here was an email in my inbox. Subject: Matt Carpenter.

If I’m burying the lede a bit on this story, it’s only to accentuate how conveniently timed this all was. Matt Carpenter is who I’m writing about this week. Specifically, I’m writing about how pitchers are feeding him sliders. I didn’t come up with this idea, though. Zach Gifford (@zjgifford on Twitter) did, and by the time it hit my inbox he’d done quite a bit of research. I was confused at first. The email said it was from Zach Gifford, and I’ve read and liked his writing -- but like, a whole story? Too good to be true! It was real, though. Some research, a few lines to follow up on, and a thesis. Deus ex machina. As I sit down to write this, I can’t help but marvel at how great life is sometimes.

Where to start? At the beginning, of course. Matt Carpenter has repeatedly changed the way he hits in the majors, to great success at each turn. One thing has remained constant, though. Whether in his high-contact, singles-hitting 2013 or his dingers-and-line-drives power-hitting 2018, Carpenter has done his damage on fastballs. That’s one of the benefits of his always-elite batting eye -- whether he’s driving or slapping, his selectivity lets him focus on fastballs in zones where he wants to swing.

The flip side of being a fastball hitter is hitting secondary pitches poorly, but for the most part Carpenter has been able to mitigate that problem by simply not swinging. I did a little digging into FanGraphs pitch values recently for an unrelated article, and I generally like the concept. While it’s noisy in small samples, the idea of assigning credit for a ball and debit for a strike in addition to the more easily measurable in-play results is compelling. Doing it via some kind of Markov chain, linear-weight concept is right up my alley. Take a look at Carpenter’s pitch-level batting value in his career:

While a great deal of the value Carpenter has accrued is from crushing fastballs, he’s also for the most part done a good job dealing with everything. In the case of curves, pitchers haven’ really located them for strikes, and he’s been able to take his way to value. When it comes to sliders and changeups, however, there’s more of a problem.

Now, that could be a few things. It could be an artifact of pitch systems having trouble categorizing the difference between sliders and curveballs. It could be noise based on which ones he’s seeing more against good pitchers. There are plenty of reasons to wonder if it’s just noise. There are plenty of reasons, though, to think it might be a real trend -- a scary one for the Cardinals.

Take a look at Carpenter’s swinging strike rate on sliders, changeups, and curves since 2015, when he revamped his swing to emphasize pull power:

That’s a bigger sample size, and it’s a worrying showing against sliders. Zoom in and look at 2018-2019, and the trend has accelerated:

So, okay. Theory: Matt Carpenter has trouble with sliders because they resemble fastballs more, which makes him more likely to start his swing, but he’s not a great breaking ball hitter. That’s at least plausible, and fits with him being worse against changeups than curveballs as well. Curves are a different beast usually -- more separated in speed even if they tunnel similarly. For whatever reason, he seems to pick them up better.

Well, it’s cool, right? Surely pitchers haven’t noticed this. Ugh:

It looks like pitchers are starting to catch on. Carpenter is facing more sliders this year than he has in any full season, and it’s a trend that started last year. He’s also facing more changeups, and only marginally less curveballs -- pitchers are just terrified of throwing him a fastball, and you can see why.

Now, maybe pitchers throwing Carpenter a million sliders is the natural evolution of things, but it’s not a game changer. After all, Carpenter has a tremendous batting eye, and he’s mostly able to lay off bad breaking balls. To really be lastingly effective against Mr. Plate Discipline, you need to be able to come into the zone, and that’s a whole different game.

Okay, so let’s say Carpenter wins the in-zone out-of-zone battle and forces pitchers to throw their secondary pitches in the zone. What’s his prize for that? Well, take a look at his wOBA on pitches he connects with in the strike zone since 2015:

Just as a point of comparison, league average wOBA on contact is .389 over the same time frame. Yeah, okay, I’m sensing a pattern here. Carpenter is a fearsome fastball hitter, and he’s generally a guy who puts pitchers in a bind. Stay away from the strike zone, and he’ll probably take a pitch. If you come into the strike zone with secondary pitches, he might not swing, but if he does, he does significant damage to curveballs and changeups. Sliders, though? Not so much.

You saw the pitch usage chart, but there’s one other change happening under the hood. Even in 2018, pitchers were nibbling on the bottom of the strike zone when they threw Carpenter sliders:

That’s an okay place to locate your pitches, but it does result in a lot of balls, and Carpenter’s probably not swinging at a borderline slider anyway. This year, pitchers are getting a bit bolder:

Here’s one way to think of it. Three percent of pitches to Matt Carpenter this year have been sliders that he takes for a strike. That’s tied for the highest percentage of his career. At the same time, 2.5% of pitches to Carpenter have been sliders that he whiffs on. That’s ALSO the highest percentage of his career. Another 2.7% of pitches he’s faced have been sliders he’s hit foul -- you guessed it, the highest mark of his career. Last and certainly least, he’s put seven sliders into play, good for seven outs.

The seven sliders he’s put into play tell a story. Three were groundballs, death for the heavily shifted Carpenter. Two were pop-ups, an outcome Carpenter avoids like the plague, but also, in a terrible mixing of metaphors, death for batters. Two were fly balls, but not particularly juicy fly balls. The best-struck one traveled a whopping 267 feet. xwOBA is a silly metric sometimes, but the xwOBA on these hits was a gruesome .123, the lowest of his career. Simply put, Carpenter is having a nightmare season against sliders.

Matt Carpenter’s career is a story of adjustment and refinement. Take something away from him, and he’ll find a new way to beat you. Force him to learn a new position, and he’ll adapt. At the moment, though, it looks like pitchers might have the upper hand in the ongoing battle. They’re throwing him sliders at a rate they never have before, and challenging him to do something with them. In his career, that’s been one bugaboo. This year, though, it looks like he’ll have to adapt to thrive.

One last note -- seriously, I can’t say enough what a good eye for analysis Zach has. I totally missed this about Carpenter, but it really does look like there’s something there. Thanks again!