The Evolution of Yu Darvish

If you become one of the very best in the entire world at your profession: keep doing what you’re doing. You’ll likely continue to be among the very best in the entire world. Way to go!

But baseball is a funny thing. Sports in general, really. Difference with professional sports is, you’re constantly competing against those who are also the very best in the entire world. Once you reach elite status, the clock starts ticking for the league to begin figuring you out to some extent. The talent gap among the top 1% of the world’s greatest athletes isn’t very large and baseball players are really smart. Once you’re figured out, you better find a new way to continue being the best in the world, or you’re not going to last at the top for too long. Sometimes, it’s just too late. Sometimes, you have to make that adjustment before you’re figured out, so you can stay ahead of the curve. Or so you can keep yourself healthy. One, or both, of these things appear to be true with regards to Yu Darvish this season.

Darvish has been one of the very best pitchers in the entire world for probably about six years now, but we didn’t really know it until 2012 because he was doing it in a different hemisphere.

Once he came over from Japan to play for the Texas Rangers in 2012, there hasn’t been much question about Darvish’s ability or elite status. From 2012-2013, no player struck out more batters than Yu Darvish. Only eight pitchers were more valuable by WAR. Only five if you prefer RA9-WAR. Things were going really well for Yu Darvish. Almost perfect. He seemingly had no incentive to change. Yet he has, and it’s for the better.

Most starting pitchers in the MLB throw between three and five different pitches. Some, like Justin Masterson, Shelby Miller or Chris Archer, pretty much only throw two. There’s the rare pitcher that has maybe six unique offerings, a Jake Peavy. Then there’s Yu Darvish and his eight-pitch arsenal. Darvish throws a four-seam fastball, a slider, a sinker, a changeup, a curveball, a different really slow curveball, a cutter and a splitter. (deep breath)

And they’re all pretty darn good. This presents a lot of different possibilites of how he can choose to attack hitters, and that’s what we’re going to dive into here. Specifically concerning the fastball and the slider.

Since the start of last season, Darvish’s slider has been the most valuable pitch in the MLB by our PITCHf/x run values. Part of the reason why is because it goes like this:

But the other part is because he threw it all the time. In 2013, only Ervin Santana relied on the slider more than Yu Darvish. Darvish threw it 30% of the time and that jumped up to 43% when he got to two strikes. Against right-handed batters with two strikes, Darvish went to the slider 54% of the time. That’s a lot of sliders. Which, despite the effectiveness of the pitch, poses a problem for two reasons.

First: game theory. Darvish is the commissioner and sole member of the “MLB pitchers with an eight-pitch arsenal” club, yet he still went to his slider over half the time when he got two strikes on right-handed batters. Obviously, it was working out for him, because his slider is excellent. He struck out a third of all batters he faced last season, which was the best rate in the MLB, and it was largely thanks to his slider. But Darvish has a whole host of other plus pitches he can use to get strikeouts. And even the best slider in the world will eventually start to get hit by the best hitters in the world if they know it’s coming. The more you rely a certain pitch, the more opposing batters start to wait on it. The more opposing batters start to wait on it, the less effective it becomes.

Second: health. As our own Jeff Zimmerman points out on this very site, pitchers who throw a high number of sliders (or curveballs) run a higher risk of injury due to the stress that throwing a breaking ball puts on one’s arm. Here’s an article which I’m now realizing is written by our very own Eno Sarris on a totally different site that breaks down specifically Darvish’s potential for injury. With how frequently he’s thrown his slider, there has been a cause for concern, especially given the Rangers injury-riddled season and it being the year of the Tommy John.

Numbers time.

So, last year Darvish threw his slider 30% of the time. This year, that’s down to just 13%. With two strikes, the usage has dropped from 43 to 26 percent. Against righties with two strikes, he’s throwing it just a third of the time after throwing it over half the time last year. In four June starts, he’s throwing just one slider for every 10 pitches, the lowest frequency of his career.

In graphical form:

The result? His slider’s whiff rate is up to 24% after sitting at 18% last year. The most valuable pitch in baseball is even more lethal because Darvish is preventing hitters from sitting on it by throwing it less. With two strikes, he gets a swing-and-miss 35% of the time, compared to 26% last year.

So what’s Darvish going to instead?

A little more sinker and a little more curve, but mostly the four-seam fastball. Darvish is throwing his fastball 43% of the time after using it less than a third of the time his first two seasons, with a notable increase of usage on the first pitch of at-bats, where he’s now throwing it a little over half the time. After two seasons of getting first-pitch strikes at below league average rates, Darvish is now above league average at getting ahead in the count, which he’s doing 61% of the time.

If there’s one flaw to be found in Darvish’s game, it’s been his walk rate. His first season in the bigs, he walked 11% of the batters he faced. You never want that number to be two digits. Very few pitchers can sustain success with a two-digit walk rate. Last year, it snuck just under the dreaded two-digit figure at 9.5%. This year, it’s down to 8.6%. Darvish’s slider breaks horizontally more than any pitch in baseball. Fastballs go straight. It’s no surprise that Darvish is posting a career-best walk rate by getting ahead in the count and throwing fewer of the bendiest pitch in baseball and more of the straight ones. It’s not like he’s throwing some slouch fastball either. It sits 93 mph and can touch 97. And it’s not like Darvish is losing any of his effectiveness by throwing less of the slider. His ERA and FIP are at career best marks and his strikeout rate is still the best in the league.

Yu Darvish was already one of the very best pitchers on the planet yet he still chose to adjust his approach before hitters could adjust to him. His slider has been arguably the best pitch in baseball over the last two seasons. This year, he has more than halved it’s usage. As a result, it’s become an even deadlier pitch and he could be saving his arm, and his future, in the process.