Tuesday, April 30, 2013
R.A. Dickey’s new knuckleballPosted by Noah Woodward at 3:02am
Last week, R.A. Dickey announced that he has adjusted his mechanics in an effort to play through pain that in his neck and upper back. The knuckleballer's velocity is down roughly two mph as a result of the nagging injury, and yet he has elected not to spend time on the disabled list. On Sunday, Dickey went seven innings and gave up three earned runs on four hits. Dickey threw a quality start, though his knuckleball hasn't appeared to be very effective. We learned Monday that he will have an MRI this week.
To ensure that his knuckleball crosses the zone at its normal level, Dickey said, he has to “start it higher.” Essentially, Dickey has shifted his vertical release point upward and his horizontal release point a bit further away from his right ear. Depending on what time period you choose as a reference point, the shift in release point seems to measure as a few inches rightward and upward—nothing drastic, but still significant.
Dickey’s average knuckleball velocity was down at its lowest level of the season on Sunday, and the trend doesn’t look encouraging.
Reason to worry?
On the surface, Dickey obviously isn’t blowing us away in 2013. Dickey’s FIP is a full run higher this year than it was last year, He is walking hitters more often, and yet his strikeout rate hasn’t dropped significantly. These statistics need some time to stabilize, however, and it is more appropriate for us to examine Dickey on a deeper level.
Let’s look at the sabermetric results that Dickey is getting from his knuckleball thus far in 2013. This season, hitters are swinging at fewer pitches outside the strike zone (25.4 percent) than they were in 2012 (33.3 percent). Additionally, when hitters do swing at pitches out of the zone, they are making contact at a much higher rate this year in comparison to 2012. This combination doesn’t bode well for Dickey, and it doesn’t surprise me that he is striking out hitters at a lower rate than he was last year. If Dickey can’t induce hitters to chase the knuckler more often, his lower strikeout rate will be here to stay.
So long as his knuckleball is moving at the level it has in the past, Dickey’s new release point doesn’t present any issues. However, the swing rate data I presented above indicate that perhaps Dickey’s knuckleball isn’t as effective as he works through his back pain.
We can break Dickey’s results down even further. I’ll compare levels of PITCHf/x movement observed for this pitch over Dickey’s past few starts to the levels we witnessed in 2012. If we see any major differences in movement caused by Dickey’s altered release point and velocity, the pain is a relevant issue. If not, Dickey’s disappointing start to the season may start to turn around.
What makes a great knuckleball great?
As you might expect, analyzing knuckleball PITCHf/x data is tricky. John Walsh wrote a seminal piece on knuckleball movement here at The Hardball Times in 2007, and his work will allow us to examine the characteristics of an effective knuckler.
To briefly summarize, a knuckleball typically moves anywhere between -10 and 10 inches horizontally, and between -10 and 10 inches vertically (before accounting for the effect of gravity). While most pitches consistently have well defined levels of movement, knuckleballs obviously don’t. I won’t go into the physics of knuckleball movement here, because a graduate degree in physics isn’t a prerequisite for fantasy baseball success. Alan Nathan has done extensive research on the subject, and I’d recommend checking out his website if you’re interested.
Here’s what we do know about knuckleballs. The more they move (horizontally and vertically), the more effective they are—but you didn’t need me to tell you that. Walsh created classifications for these different levels of movement, and his analysis of Tim Wakefield’s knuckleball revealed that OPS against “large movement” knuckleballs was almost 300 points lower than OPS against “small movement” knuckleballs. Pitch sequencing obviously plays a role here, but comparatively, “large movement” knuckleballs are better pitches than “small movement” knuckleballs. Walsh didn’t have much data to work with back in 2007, but I was able to verify his findings for Dickey.
If Dickey is throwing more small movement knuckleballs this year, we can’t expect him to achieve the same results he did in his spectacular 2012 season. Let’s look.
What do we see?
Below, I’ve plotted horizontal and vertical movement on Dickey’s pitches. Dickey’s entire 2012 season is represented on the first graph, and his two most recent starts are the next two graphs. The green dots on the first graph were classified as knuckleballs, as are the blue dots on the next two. Don’t trust the pitch classifications, however, as PITCHf/x classifications for knuckleballs can often be incorrect. These misclassifications aren’t really an issue for us, though. Almost nine out of 10 pitches that Dickey has thrown this year have been knuckleballs.
Recall the Walsh study that I mentioned earlier. Small movement knuckleballs are hit often, and they are often hit harder than the average knuckleball. I’ve defined medium-large movement areas with black rectangles above. You’ll notice that Dickey has been throwing a lot of small movement knuckleballs in 2013. He also threw fewer medium-large movement knuckleballs last Sunday than he has all season. Many factors affect knuckleball movement (weather, wind, etc.), but I’d guess the drop in movement isn’t a coincidence.
The fact that Dickey emerged from his previous start relatively unscathed is a minor miracle. Those who watched Sunday’s start can confirm that Dickey threw a far too many hanging knuckleballs. This one might be a strong candidate for “worst pitch of the season” thus far. Even if the right-hander’s MRI results don’t reveal any significant damage, Dickey should be fighting through this pain in the training room—not on the mound.
Noah can be reached via email at nowoodward15 AT gmail.com. You can check out his other articles here.