Identifying Baseball’s Most Unhittable Pitches, So Far

Advancements in baseball research, and in our understanding of the game, have made it more difficult to be satisfied with a statistic. More and more, we’ve become aware of the holes, of the problems, of — sometimes — the game-theory considerations. Batting average was left behind when people realized singles and doubles aren’t the same thing. On-base percentage isn’t as good as park-adjusted on-base percentage. It’s great to have wRC+, but what was the quality of competition? To what extent did a hitter get lucky or unlucky? Everything can always be questioned, infinitely, and we’ve all become more able to perform the questioning.

Below I’m going to present a statistic that would’ve made me the happiest about six or seven years ago. Below, we’re going to review this season’s most unhittable individual pitches, as determined by contact rate against. After all, what better way to show which pitches are great and which pitches aren’t, than by looking at how often they’re hit by swings? Is this not one of the ideal measures of dominance?

Of course, it’s a lot more complicated than that. Most of us get that now. All pitches thrown are interconnected, all having something to do with one another. It isn’t fair to just strip them of context and examine them independently, because they’re not independent. There’s also the matter of counts, and the matter of when a pitch is and isn’t being thrown to miss a bat. Sometimes pitchers want contact. Some other times, a pitch is effective because hitters don’t try to swing at it in the first place. To isolate one pitcher’s pitch is to leave a lot of the story out. Why is a pitch good, or not good? Is a slider better because of the same pitcher’s fastball? If Pitcher B has a really good changeup, what if Pitcher A threw that same changeup? What if Pitcher B only ever threw changeups? Once you start thinking about game theory, it’s almost impossible to stop the train from rolling. Everything is complicated. Everything can be argued for the rest of your waking days.

But my response to all that today is: whatever. Sometimes it’s just fun to look at what’s been an unhittable pitch. A less-interesting alternate headline would’ve been, “Identifying the Pitches That’ve Been Hit the Least Often, So Far.” All this is going to be is a contact-rate leaderboard, but you could learn something from it, even if you don’t learn everything. In short, this stuff is fun to think about, even if the reality is more complex than we might like.

Numbers were compiled from Brooks Baseball and from the Baseball Prospectus PITCHf/x leaderboards. I combined all individual pitches thrown by both starters and relievers, then I eliminated all those that hadn’t yet been swung at by hitters at least 50 times. So, the numbers you see below come with a 50-swing minimum, which is arbitrary but good enough for me. Contact rate is simply contact over swings, or if you prefer, non-whiffs over swings. Against all pitches, hitters generally make contact about four out of every five times they offer.

Now then, the most unhittable pitches of 2013 through August 20:

1. Danny Farquhar curveball, 32.7% contact
2. Jordan Walden slider, 39.4%
3. Aroldis Chapman slider, 44.3%
4. Pedro Strop slider, 44.3%
5. Josh Outman slider, 44.9%
6. Aaron Loup changeup, 44.9%
7. Patrick Corbin slider, 45.1%
8. Boone Logan slider, 45.5%
9. A.J. Ramos changeup, 46.2%
10. Phil Coke changeup, 46.3%

As you’d expect, we don’t see any fastballs, seeing instead a bunch of put-away pitches thrown for the very purpose of making batters miss. There are six sliders, three changeups, and a curveball, and the curveball in the lead is in the lead by a bunch. You’ll also notice that there are nine relievers and one starter, with Corbin’s slider leading the way among guys who see the first inning. Relievers tend to get more whiffs, because relievers want to get more whiffs. Starters try to be more efficient, which makes Corbin’s slider all the more remarkable.

Probably, you want visuals, so here are visuals of the top five, plus a Corbin bonus.

PATRICK CORBIN SLIDER

• 297 swings
• 163 whiffs

JOSH OUTMAN SLIDER

• 107 swings
• 59 whiffs

PEDRO STROP SLIDER

• 106 swings
• 59 whiffs

AROLDIS CHAPMAN SLIDER

• 61 swings
• 34 whiffs

JORDAN WALDEN SLIDER

• 66 swings
• 40 whiffs

DANNY FARQUHAR CURVEBALL

• 55 swings
• 37 whiffs

Clearly, we can be the most comfortable with Corbin’s sample size. Farquhar is 14 consecutive batted curveballs away from dropping out of the top ten completely. But this post is also specifically about looking back, and if we take something from the numbers, it’s that Farquhar probably won’t encounter a stretch of 14 consecutive batted curveballs. While it might not in truth be baseball’s most unhittable pitch, that’s what it’s been to date, as hitters have to think about Farquhar’s mid-90s fastball and low-90s cutter. The curveball has been a big reason for his 2.16 xFIP, which is the fifth-lowest in the majors.

While we’re here, we might as well take a look at the other end of the spectrum, just for funsies. The top three most hittable pitches of 2013, through August 20:

1. Ryan Dempster sinker, 98.6% contact
2. Aaron Harang changeup, 97.5%
3. Bronson Arroyo four-seamer, 95.7%

I have not prepared .gifs of those, nor do I ever intend to.