Following up on Adam Wainwright’s curveball

Back on June 29th, I wrote a post titled “Adam Wainwright’s flattened curveball.” I started the piece by saying that the 2016 season has been “anything but smooth” for Adam Wainwright, and roughly two and a half months later, this statement still pretty much holds true as the now 35-year-old righty has accrued a 4.45 ERA (3.64 FIP) over 29 starts and 176.0 innings pitched. While these are not terrible numbers (they’ve allowed for a pitching staff-leading fWAR of 3.2), they are not necessarily what we have grown accustomed to from the Opening Day starter.

In the June post (which was mentioned on ESPN’s broadcast by Dallas Braden), I wrote primarily about pitch movement — hence the inclusion of “flattened” in the title. I concluded that Wainwright’s curveball, though always a two-plane breaker, was experiencing too much side-to-side movement in 2016, which was negatively affecting the pitch’s up-and-down (aka “12 to 6”) movement. Today, I will take it one step further by discussing location and spin rate — a statistical measure made readily available to the public by MLB’s Statcast through baseballsavant.com.

Before we begin the location and spin rate discussion, let’s first take a look at the results data for Wainwright’s curveball. As I have stated in the past, I do not put too much weight into individual pitches’ results data because they simply do not tell the whole story, especially with the heightened awareness around first-pitch strikes, the importance of pitch sequencing, etc. That being said, this is the best we have right now, and when a difference is present, it is definitely something worth noting.

I must first mention the disparity in sample size. Wainwright obviously threw more curveballs from 2007 through 2015 than he has thus far in 2016. This makes the results from 2007 through 2015 more reliable than 2016’s single-season results. However, the statistics found in the final two columns stabilize sooner than batting average, slugging percentage, and isolated power, and as you can see, Wainwright is way down in both. Thus, keeping sample size in mind, Wainwright’s curveball effectiveness is down across the board in 2016.

Let’s start with the easier discussion point — location:

It does not take advanced analysis to see that Wainwright has not located his curveball well this season (bottom right heat map). In fact, with a core location hovering around middle-middle, I’m surprised opposing hitters haven’t done even more damage against the pitch.

A pitch’s location is directly affected by its ball flight out of the hand to its resting point in the catcher’s mitt. Keeping my “flattened curveball” post in mind, it makes sense that the core location of Wainwright’s 2016 curveball is higher than where it has been in the past. And up until the inception of Statcast, this analysis would likely end here because, as writers, we would not be able to explain the reasoning behind Wainwright’s poor curveball location.

Enter spin rate (measured in revolutions per minute, or RPM). You should read Mike Petriello’s article on the topic if you have time.

After some number crunching using Baseball Savant’s Statcast search function, I settled on 2700 RPM as the cutoff for a “really good” Wainwright curveball. I will now do my best to explain the choosing of this value for the cutoff. All 756 curveballs thrown by Wainwright in 2016 reached at least 2200 RPM. To find the cuttoff, I narrowed the search by adding 100 RPM until zero Wainwright curveballs registered. When I got to 2700, I saw the biggest incremental drop-off — from 518 at 2600 down to 256 (a ~50% decrease). I feel comfortable stating that one-third of Wainwright’s curveballs fall in the “really good” category.

Now, as with anything in baseball (luck plays a role in many outcomes), there are clear outliers — such as a Yoenis Cespedes homer on a curve with what I consider a “really good” spin rate of 2742 RPM versus a ground-ball double play on a curveball with a “meh” spin rate of 2599 RPM.

Bottom line

While I don’t know if spin rate is something a pitcher can openly control, September has been a positive month for Wainwright’s curveball so far. He has thrown 49 curveballs this month, and 22 (44.9%) of them have possessed a spin rate of 2700 RPM or greater — a rate he has not experienced since April when he eclipsed 2700 RPM 45.8% of the time. Plus, when he is spinning the curveball above 2700 RPM, he is in turn getting a desirable location:

If the Cardinals want to make the playoffs, they are going to need Wainwright at the top of his game. There is no better place to start than getting his Uncle Charlie back on track.

Credit to BaseballSavant.com and BrooksBaseball.net for data used in this post.