You know who's a fantastic pitcher? R.A. Dickey. So we should talk about him a lot, because it's more fun to talk about fantastic players than it is to talk about terrible players. I mean, when you're talking about terrible players, everything's so negative. It can be comical, but with fantastic players, we're reminded that these are the best talents in the universe. That we know of.
Anyway, I'm a sucker for PITCHf/x analysis, so we turn to PITCHf/x genius Dan Brooks at Baseball Prospectus. He was curious to see how much Dickey varies his knuckleball speed and movement depending on the count. He could compare Dickey only to Tim Wakefield, since it's not like we have a giant sample of knuckleballer data from recent years, but his findings are of interest. Click through and see neat graphs! And also see the words that I've copied below.
According to the man himself, R.A. Dickey varies the speed on his knuckleball according to the situation. But how much, and in what way? Is this a common feature of knuckleballers, or relatively unique to Dickey?
You can see that both pitchers actually varied the speed of their knuckleballs by the count, with more speed variability when the count was more pitcher friendly (such as on 0-2 or 1-2) than when the count was hitter friendly (such as on 3-1 or 3-0). But, you can also see that R.A. Dickey is varying the speed of his knuckleball over a much bigger range, with mph variability of ~4.5, whereas Tim Wakefield’s variability was closer to ~3mph.
Wakefield’s function is actually noisier than Dickey’s, and the trend is less clear. Still, there’s evidence that Wakefield too got more knuckleball movement when he could chance it.
What have we learned? Well, knuckleballs are not totally out of the pitcher’s control. When pitchers are ahead in counts, the knuckleball has both greater movement variability and greater speed variability— and more variability means it’s harder to hit.
So simple, so interesting. Even when a pitcher says something like "I vary my speed and movement more when I'm ahead in the count," it's great to see such statements confirmed by data. Helps to drive the significance home.