Should Michael Wacha scrap his cutter?

2013 was a promising year for Michael Wacha. One year removed from being drafted in the first round (19th overall) by the St. Louis Cardinals, the 21-year-old was pitching for the organization’s big-league club in the World Series against the Boston Red Sox. This came after fending off divisional series elimination in a tough road environment against the Pittsburgh Pirates and earning NLCS MVP honors for his two scoreless starts against the Los Angeles Dodgers.

Yet, despite early success on the league’s biggest stage, questions arose about Wacha’s staying power as a starting pitcher (long before we even learned of his persisting shoulder issues). After all, he was essentially a two-pitch pitcher — deploying a low- to mid-90’s fourseamer and a mid- to high-80’s changeup. Both pitches followed essentially the same ball flight toward home plate, with the changeup exhibiting more arm-side run (as you’d expect). Thus, a pitch he didn’t begin throwing until his 10th Major League outing in 2013 — the cutter — became a pitch he used more frequently in his first full season (10.53%), and its usage has increased in each season since — 12.47% in 2015 and 16.78% in 2016.

On the surface, the cutter’s introduction to Wacha’s repertoire made a whole lot of sense. He already possessed two pitches with arm-side movement. Sure, he threw a curveball as well, and while it does experience the desired glove-side movement, its success comes from prioritizing downward (over horizontal) movement. Plus, four years into his MLB career, the curve still isn’t a pitch he is comfortable turning to on a regular basis (with a career usage rate of 10.44%).

He turned to the cutter to provide hitters with a differing ball flight to think about out of his hand. Though a cutter doesn’t experience anywhere near the amount of glove-side movement possessed by a slider, when its movement is compared to two pitches with arm-side run, a measurable difference does indeed exist. This doesn’t even begin to take into account the difference in velocity — a key factor for keeping hitters honest — as it’s slower than his fourseamer but faster than his changeup.

Theoretically, Wacha had introduced a pitch to perfectly complement his repertoire — a repertoire that had already proven capable of success at the highest level. Unfortunately, in practice, the pitch has not yet been what had Wacha originally hoped for, despite small-sample-sized success in 2014. Further, the pitch’s worst season statistically took place after reports that he specifically focused on its development over the offseason — going as far as calling it a “new pitch” even though PitchF/x clearly shows he had already thrown it in the two seasons prior.

Remember, independently, I do not place too much value in individual pitch results. Not only because the existence of batted ball luck, but also because we do not yet know the value added (or subtracted) from proper (or improper) pitch sequencing. Instead, I like to focus on measures in which the pitcher has more (but admittedly, not complete) control over, such as whiff rate, ground ball rate, or line drive rate. That being said, when you pair individual pitch results up with another concrete aspect of the pitch — such as a location heat map — I truly believe you can learn more from the results you are seeing.

This is where I want to address the results against Wacha’s cutter. I was blunt about the pitch last night on Twitter, but for those who do not follow me, I will now provide my take in words instead of an emoji. The pitch has been downright garbage for Wacha thus far, particularly against right-handed hitters who absolutely mashed against it last season to the tune of a .310 isolated power (or .634 slugging percentage if that’s what you prefer). But Joe, I thought you don’t place too much value in individual pitch results, you ask?

And you’re right, I don’t. That’s why I have embedded the following (via Baseball Savant):

Yes, you’re seeing that heat map correctly. For a pitch that breaks down and away from right-handed hitters, the core of this heat map is located almost perfectly — I say almost because the location could technically still improve if moved one deviation outward. Yet, as I already noted above, the pitch still struggled mightily in 2016.

But maybe most of the damage we are seeing are on pitches he left up in the zone? OF course, this accounts for some of the damage (as shown by this mammoth Chris Carter home run), but certainly not all of it (Willson Contreras home run), either. In fact, and yes, I understand that we are dealing with a small sample size here, righties slugged .461 on cutters located in the bottom portion of the zone.

If located properly, the next logical step in explaining why a pitch has struggled is the actual pitch itself, from a PitchF/x standpoint. Because frankly, it’s hard to place the blame on batted ball luck when a good portion of the batted balls are raked and going for extra bases. Well, look no further than Wacha’s player card on BrooksBaseball.net, specifically the Scatter Chart section. On average, the cutter exhibited 2.08 inches of glove-side movement in 2016.

Now, you don’t learn much from a single pitch’s horizontal movement, and while there is a measurable difference from the arm-side horizontal movements of fourseamer (4.5 inches; 6.58 inch difference) and changeup (7.5 inches; 9.58 inch difference), 2.08 inches still isn’t much. Visually, compared to a spinless ball, the magnitude of the pitch’s average horizontal movement rivals that of a mere paperclip. To put it in perspective, Mariano Rivera’s cutter maxed out at 6.04 inches of horizontal movement in the PitchF/x era.

Bottom line, it just may be time for Wacha to return to the approach that was so successful in his debut season. We all acknowledge that his repertoire would benefit from a pitch with glove-side movement, but the cutter simply has not been that pitch for him up to this point. And who knows, maybe Wacha’s return to the “fastball-changeup, flash a curveball” approach will lead to a positive impact on his fastball command as well — something he has struggled with for essentially his entire career.