Michael Wacha’s Curveball Is, Well, It’s Not Good

One of my favorite articles published in recent VEB memory was alum Lance Brozdowski’s dive into Michael Wacha’s curveball last spring. I’ve talked about this article a few times, but it was a really incisive dive into why a pitcher might throw an honestly pretty poor pitch. The upshot of it was, Wacha was using his curve to steal strikes early in counts, because he couldn’t put batters away with it.

Now, in 2018 that kind of worked. His curve wasn’t great, but it was at least serviceable. He threw it 15% of the time (27.6% of the time on the first pitch of an at-bat!), and while it didn’t miss many bats, there was some method to the madness. Wacha’s plan was to pitch backwards by using his curve to set up his changeup, and in roughly a third of the plate appearances he started with a curve, he got a called strike to start things off right. There were warning signs -- he only got a swing and a miss four times, and Kyle Schwarber (who homered on a first pitch hook) and the Cubs in general were aggressive about swinging at curves in the strike zone. Still, at least he had a plan.

Why did Wacha use his curve so oddly in 2018? Essentially, he had no faith in the pitch’s ability to get swinging strikes. Among pitchers who threw 100 curveballs in 2018, Wacha generated the 11th-fewest swings. He also had a bottom-quartile whiff rate when batters did swing. Put those together, and he generated swinging strikes on only 6% of his curves. That’s less swing-and-miss than he got on his fastball -- yeesh. In any case, Wacha mainly missed the zone with his curve (42% zone rate, basically league average for curveballs) and sometimes got called strikes. He correctly diagnosed that this should be a first-pitch kind of thing -- 46% of the curves he threw last year were on 0-0, a staggering figure.

Those blah results on curveballs might have been a warning sign, but Wacha has continued down the same path this year -- 25% curveballs on the first pitch, and half of the curveballs he’s thrown have opened at-bats. The problem is, if Lance identified this trend last May, advanced scouting departments for other teams have probably figured it out by now. Those first-pitch curves are finding the strike zone less, but they’re generating more swings when they do find the zone. Batters haven’t really started ambushing the pitch yet, but they’re heading that way.

Failing to get strikes isn’t the end of the story when it comes to Wacha’s curve, though. Given that he’s not generating a lot of swings, he needs to throw it in the zone to be effective, and that means batters get to swing at in-zone curveballs. In something of a theme, Wacha somehow made it work in 2018. Batters put 27 curves into play in 2018, and they performed badly, to the tune of a .222 batting average and .481 slugging percentage. That’s serviceable stuff -- the kind of numbers Wacha could be happy with. The only problem was, they were a giant fluke.

How giant of a fluke are we talking? Well, let’s just say he gave the defense a workout. Of those 27 batted balls, 30% were line drives. One ball went 400 feet and became an out thanks to an excellent route from Tommy Pham. Two nearly took off Matt Carpenter’s and Jose Martinez’s heads at the infield corners. The eye test makes it look like fielders saved Wacha’s bacon, and advanced numbers agree. While he allowed a lower-than-average .294 wOBA on contact, his xwOBA (what the exit velocity and angle say the hits “should” be) was a garish .436. In other words, when people put Wacha’s curve into play, they hit the ball tremendously hard and at dangerous launch angles. They just happened to hit it right at fielders.

Those chickens have come home to roost in 2019. It’s still small-sample season, especially when it comes to a single pitch, but the damage has been severe. Batters have put eight curveballs into play this year. They’re batting .500 with a .750 slugging percentage. In 2018, Wacha was still occasionally able to get strikeouts with his curve -- he recorded eight strikeouts that ended in a hook, which is obviously not great but is at least a number higher than one. This year, yeah -- he has one. That one was a lovely breaker to Matt Adams, and let’s look at that one, because it’s probably the most visually appealing curve he’s thrown all year.

That’s a great two-strike curveball -- either Adams is sitting down, or it’s a ball. That’s not what most Wacha curves look like, though. My lasting Wacha curveball memory is the hanger that Kyle Schwarber caught and sent directly to the batter’s eye last June. It’s basically what you’d imagine - a curve that just spins and doesn’t break enough. That’s the bad Wacha curve, and it happens more than I’d like.

Now, anyone can throw a hanging breaking ball. That shouldn’t be disqualifying for a pitch, but when you aren’t generating many swings, the odd bad pitch is significantly more deleterious. Simply put, Wacha can’t really afford to throw this many curves if he’s not getting a boatload of called strikes, and he doesn’t locate the pitch well enough to fill that boat.

The really frustrating part of all of this is that Wacha has a significantly better breaking pitch in his arsenal. It’s not one he’s afraid to throw, either -- he’s sitting on about 20% cutters this year, and the cutter plays. Some pitchers throw a cutter more or less as a gimmick -- a bending pitch that can change hitters’ timing but shouldn’t be used heavily. That’s not Wacha’s cutter. It sits expertly between his fastball and his changeup -- the vertical break of the change, a horizontal break halfway between the two, and velocity that can sit anywhere from change-plus to fastball-minus.

The cutter has generated 17 whiffs this year, compared to the curve’s five. Batters swing and miss at 12% of Wacha’s cutters (11% in 2018), more than double the rate they flail at his curveball. It’s essentially a hard slider, and that offsets his fastball/changeup forte much more effectively than a lollipop curve ever could. Want a comparison that sadly doesn’t reflect well on the current Cardinals coaching staff? Look at Luke Weaver, who started throwing a curve less and a cutter more this year in Arizona. He’s essentially the Wacha starter kit (devastating change, lively four-seam, and that’s it), and he’s turned a cromulent cutter into great results.

I recapped the Wacha start against the Braves this week, and it was heartbreaking. Wacha’s been a valuable Cardinal for years, and even in his injury-hampered 2018 he provided some league-average depth innings. This year has been hard to watch. It’s not just because of the curveball -- his velocity is down across the board, and batters are doing better against his fastball than ever. Still, I think a lot of these problems could be fixed if he would just scrap the curve. It was a neat parlor trick in 2018, but the league is onto it this year.