What’s going on with Brett Cecil’s curveball?

The St. Louis Cardinals completed a three-game sweep of the Atlanta Braves yesterday — improving their 2017 record to a respectable 16-14 — and for that, I am undeniably excited. At the same time, as this site’s resident pitch analyst, I cannot help but think about Brett Cecil’s curveball to Freddie Freeman in the bottom of the eighth inning. In case you missed it (the Blues were playing, so that’s understandable), Cecil allowed the game-tying run on an opposite-field home run by the Braves first baseman.

As you can see, courtesy of BrooksBaseball.net, the 84.9 MPH curveball was located squarely on the outside corner, and it was set up fairly well from a velocity standpoint (5.1 MPH slower than the cutter prior). But the pitch landed higher than desired (Yadier Molina actually tapped the dirt with his mitt prior to the pitch being delivered), and it was relatively tame from a movement perspective. While the home run was definitely a good piece of hitting by Freeman — he’s on fire this year, posting a 208 wRC+ through 130 plate appearances — the curve could’ve been executed better, as I already pointed out.

Honestly, it is impossible (and irresponsible, for that matter) to perform a comprehensive pitch analysis using a one pitch sample. Thus, let’s take a closer look at the state of Cecil’s curveball in 2017, as compared to previous seasons (via BrooksBaseball.net):

Remember, regarding horizontal movement in left-handed pitchers, a negative value means glove-side movement, whereas a positive value means arm-side movement.

As you can see, compared to a spinless ball, the 2017 version of Cecil’s curve is actually backing up (or moving to his glove side, similar to the horizontal movement profiles of a left-handed fourseamer or changeup), on average. Now, Cecil has experienced this phenomenon before (2015), but never quite to the 2017 magnitude. Remember, as we continue to learn the importance of pitch sequencing and tunneling, horizontal movement is rarely meant to be viewed in a vacuum. Knowing this, Cecil’s curve still “looks like” it has arm-side movement, when compared to his other pitches, but the overall effect on hitters is lessened, as we can learn through the lens of the PitchF/x system.

For a pitcher that isn’t able to consistently overpower opponents (his average fourseamer velocity is 92.00 MPH in 2017), even the smallest difference in a pitch’s movement profile can play a significant role. Speaking of movement profile, you’ll notice that Cecil’s vertical movement and spin rate are also down thus far in 2017. For curveballs, a higher spin rate means more vertical drop. It logically follows that while Cecil is experiencing his career lowest spin rate (with only three seasons of Statcast data), he is also experiencing less vertical drop. Again, I understand that the difference is slight, but it is still worth noting.

Sure, overall, Cecil is still experiencing a high percentage of swings and misses on the pitch (47.06%), which is actually up from 2016 (43.65%), but is down considerably from 2014 (57.22%) and 2015 (53.33%). Further, lefties are swinging and missing even less frequently at 35.29% (the undisputed lowest rate of his career). Bottom line, I’ll be the first to admit that much of my pitch analysis is reactionary or descriptive. Here, I am trying to get ahead of what may be a real issue for Cecil going forward. The 30-year-old lefty was signed over the offseason to get left-handed mashers out — largely because Kevin Siegrist hasn’t been able to do it up to this point in his career (and Zach Duke is almost certainly out for the year). The curve has been and will be the pitch for Cecil to rely on when facing lefties. For the bullpen’s sake, let’s hope he is able to figure it out.