Knuckleballs and Grounders

News out of the Red Sox camp (h/t Neyer) is that the Red Sox might finally part ways with Tim Wakefield. The season is still is ways off, so there is time for injuries to come up and Wakefield find a way into the rotation. But if this is the end of the line for Wakefield with the Red Sox — only seven wins shy of 200 and 13 away from the franchise record — it would be too bad. For one thing, last year was a rare one when two knuckleballers got a substantial number of innings: Wakefield and R.A. Dickey.

Looking at the two pitchers’ numbers I was struck by their very different ground-ball rates, 55% for Dickey versus just 37% for Wakefield. My main frame of reference for a knuckleballer has been Tim Wakefield, so l always assumed that there was something about the knuckleball which led to lots of fly balls. But with Dickey’s high ground-ball rate maybe it is just Wakefield’s knuckleball.

The most likely culprit with differences in ground-ball rates is pitch height. So here, on the left, are histograms of knuckleball height for the two pitchers. On the right is ground-ball rate by knuckleball height.

So, yeah, Dickey’s knuckleballs are a little bit lower in the zone than Wakefield’s. But that alone is not enough to account for the difference: no matter the height Dickey’s knuckleballs get more grounders than Wakefield’s.

Looking elsewhere, the big difference between the two pitches is that Dickey’s is about 10 mph faster: averaging 76 mph versus 66 mph for Wakefield. It looks like this plays a big part in the difference between the ground-ball rates:

For the 65-70mph range where they both throw knuckleballs (though Dickey rarely and mostly earlier in his career) they get roughly the same ground-ball rate. But once Dickey’s knuckleballs get up to the mid-70s they get tons of grounders. It seems the additional speed on Dickey’s knuckleballs don’t lead to any more whiffs (whiff rate on Dickey’s knuckleballs in 8.2% compared to 8.4% for Wakefield), but rather more ground balls.

Having two knuckleballers gives a nice opportunity to compare what is the case about knuckleballs generally versus what is unique to specific pitchers. I personally hope that Wakefield finds a way to stick around for 2011.

Quick note: Garik16 has a great three part series on the knuckle ball that looks at both Wakefield and Dickey. Part 1. Part 2. Part 3.





Dave Allen's other baseball work can be found at Baseball Analysts.

44 Comments
Oldest
Newest Most Voted
Inline Feedbacks
View all comments
Millsy
13 years ago

Interesting. Mid-70’s (to 80, WOW) are no small feat, especially considering his fastball velocity is only around 84 mph (88-89 when he wasn’t a knuckleballer, I guess).

From personal experience, my fastball was only in that low-to-mid 80’s range and I can’t imagine ever being able to put a knuckle grip on the ball and throw it anywhere near 70, let alone 80.

I’d be very curious to see some stuff about his actual grip on the ball.

Guy
13 years ago
Reply to  Millsy

If you’re interested in the grip there is this link:
http://www.metsblog.com/2011/02/19/video-r-a-dickey-teaches-the-knuckleball/
but what I think is more interesting, and what you illuded to, is the fact that he hurls it as though it was a fastball:
http://www.sny.tv/media/video.jsp?content_id=13144345&topic_id=6479520

Millsy
13 years ago
Reply to  Guy

Thanks, Guy. I agree that the second portion you talk about is an important aspect, too, directly related to grip. Without a solid grip, I can’t imagine being able to hang onto the ball with a full fastball arm motion.

Pretty fun to watch.

Anon
13 years ago
Reply to  Guy

Gotta love Reyes in the second half of that video. Always got a smile.