Zack Greinke Is Pulling a Felix

Pitch names aren’t very imaginative. What is a fastball but a ball that’s thrown fast? The ball, in fact, thrown the fastest, relative to the curveball — which curves — or to the knuckleball — thrown as if off the knuckles. The changeup is also entirely explained by the name, although this one requires you know something about another pitch. The changeup is supposed to change things up, when a hitter is looking for a fastball. It’s supposed to represent a change of speed. Absent a fastball, a changeup is nothing but a slower fastball. The changeup needs to change something up to survive.

The game has seen a lot of pitchers. For the overwhelming majority of them, we’re sitting on pretty limited information. Surely, there have been some outliers over the years, pitchers who have done unusual things with their pitches. According to conventional wisdom, a good changeup needs to be about 8 mph to 10 mph slower than the fastball. Anything less than that, it’s thought, and there’s not enough of a change of speed. The best-known exception to this idea is Felix Hernandez, who’s been known to throw changeups in the low-90s. Felix’s changeup is one of the best in the game, so he’s served as evidence that there’s more than one way to throw a hitter off with a change. Henderson Alvarez specifically cited Felix as the reason he’s willing to throw his own changeup harder. It can be rewarding to push the limits.

Zack Greinke, too, is pushing the limits. Obviously, he’s pushing the limits of un-scored-upon-ness. But he’s also become a lot more like Felix than you might have realized.

Greinke is one of those constant tinkerers. That’s neither a good thing nor a bad thing. That’s a necessary thing in order to remain successful. The league is always adjusting, and good players always need to be able to adjust right back. Every player is a work in progress, but some of Greinke’s adjustments have been more widely publicized. He’s referred to himself as maybe the most changed player in baseball in the past 10 years. Regardless of whether that’s true, Greinke will openly admit he never feels settled.

He’s always working on something. He’s forever been working on his changeup. It didn’t have the most promising origins. Pulling from an Eno article, a year and a half ago:

Take the change-up; he’s thrown it his whole career, but it hasn’t been the same pitch. “It was an awful pitch, they just wanted me to work on it,” the pitcher said of the Royals’ coaching staff. “It’s been bad for a long time.” But the hard work is paying off (“Every year it gets a little better”) […] — “It’s probably my best pitch to lefties now,” Greinke agrees.

To get a sense of the progress Greinke has made with his change, look at his usage of the pitch, which reflects his level of trust in it. From Brooks Baseball, going back to 2008, when Greinke became a starter for good:

The trend, generally, is upward. Greinke now is throwing more changeups to lefties; roughly one for every three pitches. He’s also throwing more changeups to righties; roughly one per 10 pitches. Greinke used to be thought of as fastball-slider pitcher. Now he’s more fastball-changeup guy. The slider’s still good, though, and the above plot leaves something critical out. It’s not just that Greinke’s throwing more changeups. It’s that he’s throwing more different changeups.

Covering the same years as above, here are Greinke’s fastball-changeup velocity differentials. Put more simply, here is the difference between Greinke’s average fastball speed and his average changeup speed. The trend is unmistakable.

At the beginning, Greinke featured an exaggerated velocity gap. He subsequently pulled that closer to average, but then he just never stopped shrinking the difference. From greater than 10 mph, to roughly seven, to less than five, to barely three. The gap has gotten smaller every year. This year, Greinke’s changeup is faster; his fastball is slower.

We have pitch data on this site going back to 2002, so I made some use of it. I looked at individual starting-pitcher seasons, going back to 2002, and set an innings minimum of 50. Within the pool, here are the five smallest fastball-changeup speed separations:

• 2013 Felix Hernandez, 3 mph
• 2014 Felix Hernandez, 3.1 mph
• 2012 Felix Hernandez, 3.4 mph
• 2015 Zack Greinke, 3.4 mph
• 2015 Felix Hernandez, 3.6 mph

Felix, Felix, Felix, Greinke, Felix. Greinke is tied with the third Felix. This is most certainly unusual. For Greinke, this also is most certainly effective. It’s hard to evaluate a pitch without considering its role as part of the bigger picture, but from Brooks, here’s a plot of the slugging percentages Greinke’s allowed on changeups:

Usage up, speed differential down, slugging way down. More directly, you could refer to the pitch values we have on our leaderboards. There, you’ll find that Greinke, in 2015, has thrown the most valuable changeup in baseball. Chris Sale is right behind him, then Felix. More indirectly, Greinke’s changeup is mostly a weapon against left-handed hitters, and after years of allowing a roughly 30% hard-hit rate to lefties, he’s trimmed that to about 21% the last season and a half. It’s tremendously difficult to know how good an individual pitch is. A pitch only works in the context of all the pitches. But all the Greinke changeup indicators are good, and if you’d prefer another approach, you could realize that Greinke is having a historic season. He’s also throwing more changeups than ever before. The two probably aren’t unrelated.

You want some visuals? Of course you do. A 1-and-1 Greinke changeup to a lefty:

A 1-and-2 Greinke changeup to a righty:

Greinke throws his changeup with Felix’s speed differential. He also throws his changeup at roughly the same speed as Felix’s changeup, which means he throws his fastball at roughly the same speed as Felix’s fastball. The two aren’t identical pitchers, nor are they strikingly similar pitchers. Still, they have some strikingly similar traits, in the little picture and in the big one. Greinke used to have what he called an awful changeup. Now his changeup might be his best weapon, and he’s using it in a way no one would recommend. No one except one of the best pitchers in the world, and those who’ve seen him and realized the changeup can be remarkably versatile.

At some point, Zack Greinke will be finished developing. By then, I imagine, he’ll be retired.