Plate Coverage and the Cardinals

Earlier this summer, Eno Sarris conducted an interesting interview with Joey Votto at The Athletic. Plate coverage was one of the topics of conversation, and it ultimately spun into a second article from Eno Sarris in which he identified the best young hitters in the game at covering the plate. They’re both fascinating reads. The key takeaway from Votto is summed up in this quote:

I want my scouting report to read: very balanced. I never ever want to let on that part of the strike zone is pitchable. I’ll give up something to mask weaknesses, whether it’s connected with away, up and in or whatever...

All I want to tell them is I can handle anything. I want to show pitchers I can do anything.

It’s intuitive, and yet it’s something we rarely think about as fans and students of the game. It’s a lot harder to pitch to a hitter who can’t be consistently exploited in or around specific parts of the strike zone. With that in mind, which Cardinal hitters are best at covering the plate?

Methodology

In the Sarris articles, he divided the strike zone into an 8x8 grid. He defined a “hot zone” as a wOBA (weighted on-base)-per-pitch of .115 or better. The average is .114. His data pool in one article was a little more than two years (2016 to mid-May 2018), and the other article was a little more than one year (2017 to mid-May 2018). He also had the benefit of help from Andrew Perpetua.

A few components of the Sarris research won’t quite fit with what I’m doing. I don’t have access to the Perpetua data, meaning I can’t replicate the 8x8 schematic. That leaves me with two options. Fangraphs’ individual player charts include data in a 10x10 grid (6x6 inside the strike zone). However, that data is not searchable for all players. To get the data, you would have to look at each individual player’s page and record it. I could easily find hot zones for each Cardinal, but it wouldn’t have much context without the ability to compare it to league average.

The other alternative is Baseball Savant, which produces both a detailed zone and a gameday zone, both with a 3x3 strike zone. The difference is that the detailed option has more detail outside the strike zone. Since this is mostly (but not exclusively) focused on pitches inside the strike zone, the gameday zone works just fine. It’s less detailed than the Fangraphs version and the Perpetua version in the Sarris article. However, I’m only working with this year’s data- particularly since so many Cardinals are in their first season or have limited data going back to 2017. The Fangraphs/Perpetua level of granularity might be an inhibitor for me, as we’d be looking at a lot of zones with small amounts of data. While I applaud the granularity in the Sarris articles, I don’t think that level of granularity is needed here. Moreover, using Baseball Savant data means I can search all players and place Cardinal hitters into league-wide context.

With all of that in mind, I searched for the wOBA for all hitters with at least five plate appearances concluding in each of the gameday zones (3x3 inside the strike zone, and four quadrants outside the strike zone). Each hitter’s wOBA was given a percentile ranking, and then I isolated the Cardinals. Sarris defined a hot zone as any zone better than league average. Since I couldn’t efficiently remove pitchers, I spitballed that approximately 10% of results in any zone would be from pitchers. To account for that, I’ve tacked 10% on to the mid-point (50th percentile) used in the Sarris article. Here, any wOBA result in the 60th percentile or better in part of the strike zone qualifies as a hot zone.

Results

Here are small multiple heat maps for each non-pitcher strike zone. For a few players, there are zones that didn’t reach the five plate appearance minimum. Those are presented in gray. Inside each zone is their percentile rank amongst all hitters in wOBA in that particular zone.

There’s a lot to dig through here. Before we interpret how many hot zones each hitter has, let’s take a look at the graphic above. Each player is sorted alphabetical by first name, left to right. I included both Matt Adams and Tommy Pham despite the fact that both spent significant time in another team’s uniform this year. What you see above is their complete data for the season (i.e. not just in a Cardinals uniform).

First and foremost, if you’re an opposing pitcher looking for somewhere to attack Matt Carpenter this season, good luck. He’s above average in every part of the strike zone, along with all four quadrants outside of the strike zone. It’s not a surprise, but you can rest assured that you’ll see him shortly when I show the complete list of hitters with the best plate coverage. The same goes for José Martínez, who has two below average zones and then a sea of red.

Second, a few hitters here really get in trouble when they chase outside the strike zone. Matt Adams and Tyler O’Neill in particular really struggle when they chase. Francisco Peña struggles outside of the strike zone too, but he struggles everywhere. It’s not just when he chases. On the flip side, there are a few hitters who have feasted this year on pitches outside of the strike zone while struggling inside the zone. Greg Garcia, Tommy Pham, and Dexter Fowler have been bad ball hitters this season, as well as Kolten Wong to a lesser degree.

O’Neill’s grid is a portrait in extremes. Pitchers barely even bother going down and in on him or up and away, at least not in his smaller sample size thus far. He has absolutely murdered pitches on the inner third, middle-up. The same is true middle-down in the strike zone. He has three zones in the upper 10th percentile of all hitters, and three zones in the lower 10th percentile. That’s just about as volatile a profile as you can imagine.

Which Cardinal hitters are best at covering the plate?

It’s time to answer the original question that arose after reading the Eno Sarris articles. First, here’s the breakdown strictly for pitches in the strike zone:

With the presence of Carpenter and José Martínez at the top, there are no alarms and no surprises. Carpenter and Votto have similar approaches and consistently maximize their production. Martínez’s approach is part of what helped convince analysts that his meteoric 2017 rise was not a flash in the pan. Adams and O’Neill are a little surprising, but it’s worth remembering that O’Neill has insufficient data for two boxes in the 3x3 strike zone grid. If those turn up below the 60th percentile after he reaches the five plate appearance minimum, suddenly his percentage of hot zones is on par with Molina and Muñoz. As for Adams, we’ve seen that he gives away some of the gains from his hot zones with his poor production outside of the strike zone.

For the average player league-wide, 39.95% of his 3x3 strike zone is “hot”- just under four hot zones per player. It’s 39.98% if we include the four quadrants outside of the strike zone. That’s an average of a little more than five hot zones if we count chase pitches. Here’s how it looks for the Cardinals if we include those areas:

Tommy Pham gets a boost by including chase pitches. In the meantime, Martínez ties Carpenter as the best in plate coverage on the Cardinals while O’Neill slips to third, just ahead of Pham. A large chunk of the team falls just above average- seven of the fifteen hitters in our sample have 6 out of 13 hot zones.

As for league-wide context, only four hitters in baseball have more hot zones than Carpenter and Martinez. Those four are Mookie Betts (12 hot zones), followed by Mike Trout, Nolan Arenado, and Paul Goldschmidt (11 hot zones). Carpenter and Martinez have ten, which ties them with nine other hitters for fifth best in the league. Not only are Cafécito and the Salsa King the best on the team in plate coverage. They’re also two of the very best in the league.