Matt Carpenter’s Bounceback has been Special

You, dear reader, like Cardinals baseball. That’s why you’re here. You also very likely enjoy analyzing baseball, or at least thinking about analyzing baseball. That’s why you’re reading a website dedicated to Cardinals analysis. It follows, then, that you probably love Matt Carpenter. I certainly do. He’s a Cardinal, and he’s essentially a living personification of offensive value that analytics are best positioned to appreciate. Look at him walk! Look at him hit for power! Average is for suckers anyway. For call it the last five years, I’ve brought up Carpenter to non-Cardinals-fan friends of mine as something of a badge of honor. ‘Have you heard about Matt Carpenter? He’s not a household name, but he should be. He’s so dreamy at offense.’ Did I use the word dreamy? Probably not. You get the idea, though.

This history with Carpenter made April hard for me. There’s no delicate way to put this- he was terrible. He put up 103 plate appearances and somehow only recorded 13 hits. He didn’t make up for it in power- he recorded only four doubles and two home runs out of those hits. He recorded his normal complement of walks (tons!) but still only turned in a 67 wRC+. Even worse than these surface stats, however, he looked bad doing it. Carpenter swung through strikes at an unfathomable rate. At one point in April, he was below a 70% contact rate on pitches in the strike zone. That’s just not major league caliber. Take a look at how out of place that contact rate is for him:

The depth of the contact plunge in 2018 is crazy. You see those weird flat-topped patterns in the upper left? Those are times when Carpenter went ten games without swinging and missing at a pitch in the strike zone. Zero pitches! All of the sudden he was missing a third of the pitches he swung at.

Well, it’s a month later, and Matt Carpenter just had one of the best months of his career. So much for missing pitches. It’s pretty rare to see such an emphatic turnaround, so I went to the data to see what was up. As a first pass, I looked through the last three years for hitters who put up 400 PA the previous year, at least 80 in April, and then continued playing the rest of the season. This gives me a population of hitters who we at least have some historical data for. I bucketed them by how much their wRC+ declined from the previous year. The data looks like this:

Right away, you can see that Carpenter is an outlier. He’s reasonably close to the average for biggest decliners. It also makes sense that the people who declined the most tended to have the highest wRC+ the previous year- that’s a nasty bit of regression to the mean popping up. It does seem, though, like declines in wRC+ tend to carry over at least somewhat to the rest of the season. The biggest decliners, for example, had the highest wRC+ in aggregate in the previous year but the lowest for the remainder of the year. Instead, Carpenter has been setting the world on fire since his poor April. As a general demonstration of how much of an outlier Carpenter’s May 2018 has been, here are the biggest differentials between April and rest-of-season wRC+ by hitters in the last three years.

All six of these guys hit like mortals for April and gods for the rest of the season. Two of these seasons are dumb, to put it mildly. Brandon Crawford and Scooter Gennett each have BABIP’s above .470 this May, so I’m inclined to look past those. Carpenter’s is a much less cartoonish .360, a high but not unfathomable number. Either way, though, it’s remarkable- of the 371 player-seasons I studied, he had the sixth-highest gain. It’s also pretty remarkable that Joey Votto carried a 67 wRC+ through April in 2016 before being basically exactly his old self after that- imagine the gnashing of teeth and rending of garments from Reds fans. Either way, it looks like Carpenter has been an outlier so far- people who decline tend to stay declined, not turn into fearsome hitters.

This is interesting, but I wasn’t really satisfied with this amount of analysis. Carpenter was bad, and now he’s… good… because… reasons? That’s not the way I like my conclusions. I set out to see if I could tie his contact rate turnaround to his hitting success. I sorted this same list of players by their Z-Contact%, looking for the change from the previous year to the current year’s April. Again, I looked at how that compared to their Z-Contact% the rest of the year.

In terms of his lost and re-found ability to make contact, Matt Carpenter doesn’t look like anything special. He declined by about the average of the worst 20% of contact decliners. He has since bounced back by about the average recovery of those same hitters. The difference, though, is that when those hitters recover about halfway in Zone Contact%, they also recover about halfway in wRC+. Their skills seem to have declined, and they pay a price both in contact rate and in overall batting output. Carpenter looked at that playbook, tore it up, and hit it for a double. The only other player with similar contact decline to increase his wRC+ more was the aforementioned Brandon Crawford, and he has totally fixed his contact issues (up at 91.7% Z-Contact) in addition to his laughably high BABIP.

Honestly, at this point I wasn’t really sure what to do. Matt Carpenter is part of a cohort of players whose wRC+ declined a lot from the previous year. His recovered more than almost any of theirs did. Fine, that makes sense, he started hitting the ball better. He’s also part of a cohort who lost contact skills from the previous year. His recovered about as much as theirs did- but they collectively hit worse than the previous year, whereas he is absolutely raking. Where’s the hidden variable? Maybe, I thought, he’s just better at turning his contact rate into walks and avoiding strikeouts than most of these players. That seems like a very Carp-y skillset, and one that this analysis maybe wouldn’t capture. Here I’m going to use the same Z-Contact percentile ranges as above, but look at their April vs. rest-of-season strikeout and walk rates.

Curiouser and curiouser. With his contact rate higher, you might expect Carpenter to strike out less as the season wears on, like other low-contact-April hitters do. There doesn’t appear to be much of an effect on walk rate (aside from a generally higher April walk rate as pitchers struggle with their grip in cold weather), but that seems reasonable as the pitches that Z-Contact measures are by definition in the strike zone, so not directly related to walks. Instead, he’s become a strikeout machine and his walk rate has cratered. 27% strikeouts and 9% walks is Trevor Story or Byron Buxton territory, hardly imposing hitters.

What remains, then? Well, it’s the results on contact, dummy. In April, Carpenter hit his balls in play (plus home runs) for a .240 wOBA, somewhere on the dividing line of dreadful and realllllllly dreadful. Since then? He’s run a .509 wOBA, somewhere between amazing and ‘stop using cheat codes the game isn’t fun that way.’ Here’s a list of the names who ran a higher wOBA on contact last year: Aaron Judge, J.D. Martinez, Miguel Sano, Joey Gallo, and Giancarlo Stanton. For his career, Carpenter has a .394 wOBA on contact. For this year, combining his miserable April and dominant May, it’s at .385. It looks for all the world like Carpenter just found his level in a bizarre way.

What does this mean going forward? Well, I’m not inclined to believe that Carpenter is going to keep crushing the ball like he’s done this May. The other guys on that list are giants who would look equally at home on the football or baseball field. Matt Carpenter would look equally at home on the baseball field or behind the bar at your favorite local craft brewery. Just for fun, I used an old formula for Carpenter’s plate discipline to estimate walks and strikeouts. I then combined this with a .405 wOBA on everything else, giving him a little bit of benefit for stinging the ball this year but regressing heavily towards his career line. This incredibly subjective process would leave him with a .338 wOBA. His season-to-date wOBA, taking into account the doom of April and the brilliance of May, stands at .335. Maybe after all this worry about his decline and then triumph at his recovery, Matt Carpenter is exactly where he should be this year.

I wish this conclusion were a little bit more exciting. Hot takes are fun! I came into this article hoping to write that Matt Carpenter was a true-talent 160 wRC+ hitter going forward and that he had solved the shift forever by just hitting the ball harder. To my eyes, though, it just looks like Carpenter is a quality-of-contact outlier in May- he’s absolutely clubbed the ball, to be sure, but not in a sustainable way. The good thing, though, is that it looks like his April had some quality-of-contact woes that are unlikely to persist. In the end, that leaves me thinking that Carpenter will be fine but unexciting the rest of the year- a 3 win player if his defense holds up or a 2 win player if he doesn’t. His ZiPS projection for the rest of the year is for a 120 wRC+ and 2.2 wins to add to the 1 he’s accumulated already- I’d take the under on both of those numbers but only by a bit. Sometimes, an average player is just an average player, no matter how much you want the data to show you his secret talents.

Note: all stats current through Tuesday-ish. There were a lot of data pulls in there so it’s possible I’m off a day on one set.