There's Finally a Book on Matt Carpenter


Earlier this morning, Tara Wellman sent me a link to this video of Matt Carpenter talking about his approach at the plate:

For the tl;dw crowd, Matt Carpenter speaks to his change in approach from “owning” the outside of the plate (2012-2014) to “hunting” fastballs on the inner-half (2015 and on). He goes on to recognize that pitchers have since caught on to his style and, to regain his effectiveness, he'll need to adjust again and get back to owning that outer half. It's everyone's favorite Matt Carpenter debate, and this is awesome insight.


To provide some (un)necessary context, 2019 was a disaster for Matt Carpenter. In 2018, among 278 hitters with 300+ plate appearances, Matt Carpenter’s 5.0 WAR ranked 21st and his 140 wRC+ ranked 16th. In 2019, his offensive production deteriorated. His wRC+ fell to 95 and his WAR declined to 1.2 as a result, representing the 8th largest decline in baseball among the player set. Carpenter hadn’t produced a season worth less than even three WAR since 2012, and that mark was only held back by playing time – over 340 plate appearances that season, Carpenter produced a 124 wRC+. Excluding his cup of coffee in 2011, the 2019 season was by far the worst of his career.


The picture painted by Carpenter’s peripherals isn’t any less gloomy. He struck out more and walked less. His average exit velocity in 2019 was 2.4 mph weaker than the year before and his barrel rate fell from 8.3% to 4.7%. His hard-hit rate, measured as a percentage of balls hit 95+ miles per hour, fell from 44.6% (Cody Bellinger territory) to 31.1% (more like Orlando Arcia). That 31.1% hard-hit rate was by far his lowest since Statcast began tracking in 2015.


The team and Carpenter have said they believe the problem stemmed from focusing too much on agility and not enough on strength. Obviously we don't have Matt Carpenter’s body, we can't feel it, and we don't have access to his health and strength data. I’m sure there’s something to the agility/strength tradeoff, or the team wouldn't be saying there was.


We have batted ball data, though. By looking at how hard Carpenter hit his hardest batted balls, we can see if there was any indication that he was weaker. By focusing on a max effort event, we can partially separate Carpenter's overall performance from his peak effort.

Over the course of the year, Carpenter's peak exit velocities trended down. Maybe strength and fatigue were the issues. However, in April and May (before injuries began popping up), Carpenter’s max exit velocities were awfully similar to prior seasons when he performed well. And yet, he still stunk in those months. Just as damning, he deserved his poor performance according to the expected results based on exit velocity and launch angle. The difference was more than muscle.


If you watched the video at the top of the page, maybe you've caught on that I’ve buried the lede. Carpenter talked about pitchers adjusting to his fastball-hunting style, and adjust they did:

Back before he emerged as a pull-power threat in 2015, pitchers used to throw Matt Carpenter fastballs (inclusive of cutters) about 70% of the time. When he became a power threat, opposing pitchers replaced some fastballs with some changeups. For the next few years, Carpenter found another equilibrium in which he saw fastballs almost two-thirds of the time. Sitting dead-red on fastballs worked well when Carpenter could be pretty sure a fastball was coming.


Then, in 2019, pitchers changed again. They dropped their fastball rate to Carpenter by another 8.4%. They replaced those fastballs with a mix of changeups, sliders, and curves. After the first pitch (when he saw fastballs 62.5% of the time), the mix was even murkier with only 54.7% fastballs. Overall, Carpenter was much closer to a 50/50 guess than the 70/30 he was used to.


That shift away from fastballs was evident early in the year, too, with Ben Clemens catching it in early May off a tip from yours truly. Despite the trend’s early emergence, however, Carpenter didn’t adjust. He admits as much, calling himself stubborn for maintaining his pull-happy fastball-hunting approach even as pitchers changed to counter it. Even in September/October, his best month of the year, Carpenter pulled 58.5% of his batted balls – his second highest in any month in the majors. His 128 wRC+ in that time was the high water mark of the year but would have ranked below each of his full season rates since 2015.


When hitters talk so openly about their approach like this, I like to compare how what they say lines up with the available data. So far, the narrative lines up well with what happened. In the video, Carpenter cited another possible cause (other than strength) for the ineffectiveness of his approach. Specifically, he talks about pitchers locating the ball on the outside portion of the plate in an effort to mitigate his ability to pull the ball.


That statement doesn’t really align with what the pitch data shows. In 2019, 23.5% of the pitches he faced were in the heart of the strike zone. That rate was down about 2% from 2018 but in line with what he saw from 2015 to 2017. And, contrary to popular belief, Carpenter was more aggressive attacking those meatballs in 2019 than in any prior season. Passiveness wasn't the issue.


Overall, pitchers challenged him in the entire strike zone at a similar rate to any other year. The frequency with which they located on the outer third was virtually unchanged, as was their willingness to attack the inner third. Carpenter indicated he thought location was an issue, but that doesn't appear to be supported.


If there was a shift in location within the strike zone, it was a move from high to low. All things equal, given Carpenter has historically hit pitches in the lower third of the zone better than pitches in the top third, that downward shift should have helped him. All things weren’t equal though, and the downward shift was simply a result of pitchers throwing less fastballs, which are usually thrown higher in the zone, and more junk, which is usually located lower. We're back to the breaking ball problem.


In all honestly, it’s surprising that it took this long for pitchers to make a shift this drastic. Compare how Carpenter has performed, relatively speaking, on each type of pitch:

League-wide, everyone’s better against fastballs. Fastballs are easier to hit! Even in an otherwise terrible year, Carpenter still hit fastballs pretty well. But the dropoff in Carpenter’s performance from fastballs to non-fastballs is wider than the average, especially since 2015. And yet, 2019 was the first time he saw fastballs at a rate lower than the league average. The book on Carpenter came out eventually, and it’s going to be a tough one for him to re-write.


Based on the pitch trends above, it does appear that Carpenter’s performance against non-fastballs was better when his approach was more focused on driving the ball up the middle. When you focus up the middle, you can let the ball travel a smidge further than if you’re selling out to pull it. Maybe that gives Carpenter time to recognize offspeed or breaking pitches. If he can regain some ability to go up the middle, maybe he’ll have found a successful counter.


Baseball is a game of adjustments after all, and it at least sounds like Matt Carpenter knows what adjustments he needs to make. Recognizing the problem is the first step in correcting it. Unfortunately, adjustments are easier to postulate than to execute and, at 34-years old, Carpenter's most malleable days are behind him. For a long time, he thrived as a one dimensional hitter who, for some reason, kept getting a ton of fastballs in the zone despite obvious success against them. In 2019, the script finally flipped against him.


Heading into 2020, it's important to manage expectations. Matt Carpenter isn't suddenly going to become a good opposite field hitter. After all, you know what they say about old dogs and new tricks. Maybe, though, he can recapture his success by staying through the ball up the middle. What do they say about re-teaching the old dog a forgotten trick?



Credit to @cardinalsgifs for the cover art, and to Baseball Savant and FanGraphs for the data referenced throughout this post. Also to Jeff Sullivan, from whom this title was adopted. In case Mr. Sullivan finds himself perusing an indie Cardinals site instead of whatever he's doing with the Rays - Thanks, Mr. Sullivan.