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St. Louis Cardinals: What Happened to Michael Wacha’s Offspeed?

St. Louis Cardinals Michael Wacha

Last week, I looked at Michael Wacha’s fastballs attempting to find some reason to explain why he has been experiencing annual decline. At the risk of making him “my guy,” I’m diving into Michael Wacha again this week.

I noted previously that hitters’ wRC+ has been consistently rising against Wacha’s fourseamer and cutter. Against Wacha’s fourseamer, hitters’ wRC+ rose to 134 in 2016, up from 83 in 2013. Against his cutter, batters owned a 135 wRC+, up from 60 in 2014 (I incorrectly reported this stat previously). One main takeaway is that hitters have been trending better against Wacha’s fastballs since he debuted. Given that pattern, it’s not a huge surprise that they were again better in 2016.

Against Michael Wacha’s offspeed, however, the opposite is true. From 2013 through 2015, hitters managed between a 40 and 54 wRC+ against his changeup each year. Against his curveball, batters wRC+ dropped from 137 in 2013 to 67 in 2015. By 2015, Wacha’s curveball looked like a reliable weapon.

Unfortunately, 2016 was a different story for Wacha’s offspeed. Hitters pounded his changeup and curve better than they ever had. Hitters managed a 91 wRC+ against the changeup, up from 51 the year before.

Additionally, while hitters only generated a 72 wRC+ against his curve, they hit for a much higher average against his breaking ball. An extremely low .026 ISO suppressed their overall wRC+. Given that batters hit more line drives off Wacha’s curve than 2014 or 2015, it is lucky this number wasn’t much worse. For reference, in 2014, Michael Wacha gave up a .279 ISO when using his breaking ball.

A look at contact quality against Michael Wacha demonstrates how the offensive output against him changed so dramatically last season. Over the course of just one season, variation in contact quality might be attributed to poor luck. However, an examination of Wacha’s offspeed movement and location paints a more troubling picture. His offspeed command is a major concern for his effectiveness going forward.

Contact Quality

The most obvious concern regarding both Wacha’s changeup and curveball is the rate at which batters squared up the pitches in 2016. Batters’ line drive percentage (LD%) against Wacha’s changeup jumped to 32.9% in 2016, up nearly 10% from 2015. Against his curveballs, hitters owned a 29.0% LD%, also up nearly 10% from the year prior. More line drives, generally, results in more hits and extra base hits. Initially, this appears to show why Michael Wacha struggled with his offspeed pitches last season.

However, a look at exit velocities tells a more positive story. According to Statcast, hitters’ average exit velocity against Wacha’s changeup was essentially unchanged from 2015 to 2016. Additionally, hitters’ average exit velocity against his curve dropped from 88.7 MPH in 2015 to 86.9 MPH in 2016.

The sample size on these batted balls is too small to draw predictive conclusions. However, these exit velocities might indicate that Wacha was unlucky in 2016 relative to 2015. He generated weaker contact using his offspeed last season. Yet, this improvement was not reflected in his poor results as measured by traditional metrics.

Movement and Location

Since hitters hit more line drives against Michael Wacha in 2016, I thought that less movement or poor location might have made his pitches more vulnerable.

While movement doesn’t appear to be an issue for the curve (it took a more 12-6 shape in 2016, sacrificing horizontal movement for greater drop), movement is a concern for his changeup. This pitch had more than one inch less horizontal movement in 2016 compared to 2015 (-4.89 vs. -6.16). Additionally, the pitch also had slightly less vertical movement (-25.16 in 2016 vs. -25.66 in 2015). With less horizontal and vertical movement, Wacha’s changeup would be easier for batters to square up.

The decrease in movement does not appear to be attributable to a lower arm angle. Michael Wacha had a higher vertical release point when throwing his changeup in 2016 than 2015. However, he did have the widest horizontal release point of his career last season. This may be a mechanical adaptation to preserve his shoulder strength. While this release point did not negatively impact his curveball movement, it appears to have hindered his changeup.

Location is another concern, especially for his curve. Below are his curveball heatmaps for 2015 (left) and 2016 (right).

St. Louis Cardinals Michael Wacha
Source: Baseball Savant

Michael Wacha was extremely inconsistent with his curveball location in 2016, generating two separate cores. Furthermore, he left more up and over the plate, which are, of course, much easier for batters to handle.

Location was less of a concern for his changeup. However, Michael Wacha was still more erratic with the pitch in 2016 (right) than 2015 (left):

Michael Wacha St. Louis Cardinals
Source: Baseball Savant

Both years, Wacha generated a core in the lower-left of the zone. However, his core in 2016 also extended upward. Again, this clearly would have been easier for hitters to handle.

Based on these location heatmaps, it is obvious that Wacha struggled to command his offspeed pitches in 2016. It is almost surprising that he wasn’t worse last season. This contrasts sharply with what I concluded about his fastballs previously, which he seemed to command as well or better in 2016 as he ever had previously.

Many, including myself previously, have pointed to Wacha’s 3.91 FIP as a sign that he was not that bad last season. However, his loss of offspeed command is a troubling sign. Rather than putting hitters away with his offspeed, he often gave them easy pitches to hit. Additionally, this makes the potential for a rebound appear less likely.

Thanks for reading. Check back again Thursday when I’ll dive into what is (hopefully?) my last analysis concerning Wacha. For a while, at least.

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