Michael Wacha Has Four Above-Average Pitches

Maybe it’s just me, but it seems Michael Wacha’s solid season has largely gone unnoticed among a sea of excellent pitching performances this year. His value is largely buoyed by the win column (12) because of a relatively modest 7.61 strikeouts per nine innings (K/9), but his 3.09 ERA and 1.09 WHIP are nothing to sneeze at — they rank 21st and 18th, respectively, among all qualified starters.

Wacha has largely taken teammate Adam Wainwright’s path to success this year: walk very few batters, induce a lot of ground balls and limit hard contact. Wainright has historically been more effective in limiting baserunners — only recently did his strikeout rate fall below 8.0 K/9 — but Waino has also been around a while. He really didn’t hit his stride until his age-27 season.

Technicalities aside, Wacha and Wainwright don’t have a lot in common. Waino throws sinkers, cutters and curves; Wacha lives primarily off a four-seamer while peppering in the occasional cutter, curve and change-up. However, Wacha improved one of his secondary pitches this year, and it helped him join an elite, albeit somewhat contrived, group of pitchers.

Wacha and 10 other starting pitchers have thrown four or more different types of pitches this year that have generated more than one run above average of value, per PitchF/X’s weighted pitch values. To make the list more exclusive, Wacha joins only four other pitchers who throw at least four above-average pitches and zero below-average pitches.

Wacha’s curve was the laggard until this year, finally vaulting in value from below average to above average. The chase rate (O-Swing%) on the pitch has increased by more than 25 percent since last year, corresponding with a 40-percent leap in its swinging strike rate (SwStr%), up to 12.4 percent. It’s not elite, but coupled with a ground ball rate (GB%) north of 60 percent, it has evolved from a weak secondary offering into a very reliable one. To attest: Wacha hasn’t allowed an extra-base hit off his curve this season.

The relative success of the pitch can likely be attributed to its changing composition. Wacha throws it harder than he did last year — 75.8 mph to 74.6 — as well as tighter, with less horizontal and vertical movement. I profiled Rubby de la Rosa in May when I noticed his slider had improved; its improved velocity and suppressed movement corresponded with robust gains versus opposing hitters. It seems Wacha is experiencing similar, albeit more modest, success with his curve.

So, Wacha now throws four above-average pitches, but none of them grade out, according to PitchF/X, as elite (à la Clayton Kershaw’s curveball, for example). Despite my lauding of it, Wacha’s curve is not yet excellent by any means. In fact, at 1.0 weighted runs above average, it’s barely above average, and the pitch’s somewhat pedestrian SwStr% illuminates this. But hey, at least it’s not below average.

Moreover, having a well-rounded, if not exceptional, arsenal can only be a good thing. The limited company with which he shares this “feat” — Matt Harvey, Sonny Gray, Jacob deGrom, Max Scherzer — certainly validates this notion.

Wacha’s curve is finally an average-or-better pitch, but it actually may not be his most improved pitch. The swinging strike and chase rates on his other secondary pitches have all leaped several percentage points since 2014. A pitcher’s chase rate and his strikeout rate moderately correlate positively with each other (R = .399), indicating, rather intuitively, that inducing more swings on pitches outside the zone typically corresponds with more strikeouts.

Unfortunately for Wacha, he hasn’t experienced those kinds of gains, actually seeing his overall strikeout and swinging strike rates drop since last year. It’s with his four-seamer where Wacha has lost ground, with which he has allowed the hardest contact. And he throws it almost 60 percent of the time — good for 7th-most among all qualified starters — meaning he essentially throws (one of) his least effective pitch(es) most often, explaining the relative decline in strikeout effectiveness since last year.

Perhaps it would behoove Wacha to swap out a few four-seamers for an extra off-speed offering here or there. Maybe it’s a matter of predictability. If he does shake things up by altering his approach, I can see Wacha taking an even bigger step forward next year; and considering he’s ESPN’s 17th-best starter, it could vault him into “staff ace” discussions.

Until that kind of change happens, I don’t see Wacha’s profile changing much by 2016 draft day. But that’s not such a bad thing: his above-average ground ball tendencies and stinginess with the free pass help prevent baserunners and limit damage when they’re on base. It also helps to have the game’s best relief corps backing you up.