Michael Wacha can duplicate his 2018 or soar into free agency

If Carlos Martinez is not in the rotation on Opening Day, there is only one pitcher since 2014 who has started more than five games and broke camp every season in the starting rotation for the Cardinals: Michael Wacha. The 6-foot-5 righty has had his share of injury tribulations but fiddling with qualifiers provides one angle of consistency.

Wacha enters his peak, age-27 season in his final year of arbitration before hitting free agency. Projection systems, like Fangraphs’ Steamer, peg him for the sixth most value produced in the Cardinals’ rotation. This is connected to a pessimistic 23 starts—prior injury is the best predictor of future injury—and does not factor in Martinez’s projected time off given his current ailments. Instead, it sees Wacha as a pitcher who just posted the worst walk rate of his career sitting on a deteriorating average exit velocity against over the last four seasons.

But he has changed. His fastball and curveball fell to average pitches in 2018. His cutter took his fastball’s place as his featured, hard offering and his changeup became a true plus pitch for the first time since his rookie season. Early reports from Roger Dean Chevrolet Stadium are promising from a results standpoint. But focusing on two of his secondary pitches shows one path towards duplicating 2018 and another a path towards greater success.

Last May I wrote about the noticeable differences in Wacha’s early approach to hitters. In line with the rest of the league, Wacha went to his off-speed pitches more than prior years, even with the adoption of his cutter. But he used his curveball earlier in counts, possibly to steal strikes or possibly because he never intended to use the pitch as a put-away offering.

The trend became apparent early in the season as his first-pitch curveball rate hovered around 34 percent. Although Wacha’s injury prevented us from seeing if it continued over a full-season sample, looking his 84 1/3 innings from last season as a whole, he stopped front-loading his curve as the season progressed. His rate of first-pitch curveballs ended at 28 percent.

Fangraphs’ pitch value metric tagged the pitch as slightly below average last season and a simple wOBA comparison pushes it up to an average offering on a results basis (.264 wOBA for Wacha’s curveball; .269 wOBA for all curveballs).

To my naked eye, Wacha has thrown 10 curveballs this spring in his 68 pitches. He has only used the pitch with two strikes once, turning to the pitch in 0-0, 0-1 or 1-0 counts seven times. This is a small sample, but his usage of the pitch in spring resembles strongly what he did last season with the offering. If once again his fourth pitch is an average offering, fans shouldn’t be irritated.

MLB

If Wacha is a similar pitcher to last season in other elements of his repertoire, that means his dominating changeup is back. From 2017 to 2018, his average exit velocity against on the pitch fell five miles per hour (90.7 to 85.7 mph; 85.3 mph league average for changeups in 2018). He managed to relinquish only a .267 slugging percentage against the pitch in 2018 as well, 120 points lower than the league average against changeups.

For Wacha, the trick might be using his changeup more come Opening Day. Among pitchers with at least 80 innings in 2018, Wacha’s 22 percent changeup usage fell at the back half of the top 25 percent. While the saying “use your best pitch more” often applies to breaking balls, Wacha’s changeup could benefit from an increase in usage.

Through Wacha’s small sample of spring starts, he has thrown his changeup (to my naked eye) nine times. While this in slightly under the expected usage of the pitch, aside from Wacha’s curveball usage staying steady, he has largely been a fastball-dominant spring starter. This could be to generate a feel for his primary pitch or part of a wider gameplan to build towards more secondary pitch usage as spring progresses.

MLB

Wacha’s pitch mix is relatively unique, limiting the amount of comparisons available for the righty to evolve into. Oddly enough, two who line up well are both former teammates: Luke Weaver and Marco Gonzales. Weaver possesses a similar fastball velocity to Wacha and tinkered with a Rapsodo this offseason. Gonzales is a secondary-pitch-heavy, lefty iteration who works with a much slower fastball. Current Cardinal John Gant even has a similar mix to Wacha. Gant works with a sparingly used slider and a five percent uptick in changeup usage compared to Wacha. Models exist to baseline Wacha’s usage and mix. But for them to become representative, he will need to become more reliant on his secondary offerings.

If Wacha does opt for more secondary pitches in 2019, there’s a chance his swinging strike rate creeps higher for a fourth-straight year and pushes his K/9 back over 8.0. For a pitcher in his peak-age season, heading into a free agent market that has not been kind to anybody, an uptick in stuff could be an encouraging boost for teams seeking another mid-tier starting pitcher.

Wacha’s 2019 repertoire should be a fun storyline come Opening Day.