Originally posted on Baseball Prospectus  |  Last updated 6/19/12

The knuckleball is a difficult pitch to hit because of its unpredictable movement. But few analyses have ever looked at another component of the knuckleball: its speed.

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?

In the PITCHf/x era, we really have only two knuckleballers with sufficient data to analyze, R.A. Dickey and Tim Wakefield (there are others, such as Charlies Haeger and Zink, but those pitchers have appeared only a very small number of times).

To answer this question, I pooled knuckleballs by count (1-2, 3-0, etc.) and looked at the standard deviation of the pitch mph within those counts. To visualize this data, I have plotted count, not as two separate categorical variables, but as count linear weights—the run value of being in a particular count (such as 0-2). This makes “count” one continuous axis along which to visualize data.

R.A. Dickey’s data is in the first graph:

And Tim Wakefield’s data is in the second graph:

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.

A related question is whether these pitchers have more movement variability when the count is favorable than when the count is unfavorable, which would suggest some ability to make the pitch dive or turn an extra amount in favorable counts.

Here is Dickey’s data; I removed 3-0 counts because one significant outlier in a small dataset (he rarely throws 3-0 knucklers) was dramatically changing an otherwise evident pattern:

It’s clear that when the count is pitcher friendly, Dickey’s knuckler has some extra butterfly action. How about Wakefield’s?

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. 

Ios_download En_app_rgb_wo_45

Kobe has worst game of his career against Warriors

Rams WR Stedman Bailey in hospital after being shot in head

Furious Brad Stevens blasts Celtics after lackluster game

Did Bryce Harper deserve the MVP?

Duke 5-star commit posts moving message after successful surgery

Ex-LSU commit still supports Les Miles


Report: Ray Lewis gave Bills pregame pep talk

Report: Marshawn Lynch out a few weeks to recover

Peyton Manning to miss at least two more weeks

Notre Dame DT: Committee 'spit in our faces' with ranking

LaRon Landry suspended indefinitely by NFL

Don’t blame Mike Pettine for benching Johnny Manziel. Blame Johnny.

The B1G uglies – which division leader might stumble?

Six MLB teams that will be most active at Winter Meetings

Breaking down the NFL playoff picture heading into Week 12

Nick Young seems to take shot at Kobe Bryant

WATCH: College basketball player makes 3-pointer while wobbly from concussion

The five most overrated teams in the Week 13 coaches' poll

Clemson WR calls South Carolina fans 'rude'

Jonathan Lucroy trade market bolstered by weak catching market

Michigan State lists two starting QBs on depth chart

10 storylines for Week 13 of the college football season

LISTEN: Browns fan cries on radio while ripping Johnny Manziel

Texas A&M QB Kyle Allen says he was injured vs. Alabama

Report: Maple Leafs are no longer the NHL’s most valuable franchise

All Sports News
Delivered to your inbox
You'll also receive Yardbarker's daily Top 10, featuring the best sports stories from around the web. Customize your newsletter to get articles on your favorite sports and teams. And the best part? It's free!

By clicking "Sign Me Up", you have read and agreed to the Fox Sports Digital Privacy Policy and Terms of Use. You can opt out at any time. For more information, please see our Privacy Policy.
Get it now!
Ios_download En_app_rgb_wo_45

The five most overrated teams in the Week 13 coaches' poll

10 storylines for Week 13 of the college football season

Ranking the 10 best games of 2015 college football rivalry week

Examining the Mavericks' hot start

Johnny Bench(ed): Manziel demoted to third string

Mike Trout, four years in

Tom Brady on ‘Rex Ryan!’ line call: It’s ‘in the playbook’

Five NFL teams trending downward

Not so fast, USC: Eagles Chip Kelly buys Philly-area home

The five best hockey fights from Week 7

Today's Best Stuff
For Publishers
Company Info
Follow Yardbarker