Is There a “Knuckleball Hangover”/R.A. Dickey Effect?

Does R.A. Dickey’s “dancing knuckleball” demoralize hitters? To put it another way, are other pitchers on a team helped when teammate R.A. Dickey has pitched just before they do? If there is a “knuckleball hangover,” how long does it last?Knuckleball in multiple motion

Back in March of last year, the Wall Street Journal ran a post by Michael Salfino entitled “Missing Dickey Most: The Guy After Him”:

Dickey, whom New York traded to the Toronto Blue Jays in December, baffled opponents all season in 2012 with his otherworldly knuckleball. In fact, opposing hitters were left so off-balance, confused and out of sync that the Mets starters facing the same team the next day seemed to take advantage. In these scenarios, starters posted a 2.38 ERA—even better than Dickey’s 2.73.

Baseball is built around individual pitcher and hitter matchups. So it’s unusual to find evidence that one player can actually improve the performance of his teammates. If this phenomena is to be believed (the Dickey hangover didn’t exist in 2010 and 2011), then there’s reason to believe the rest of the Mets staff will see some drop-off this season….

Coincidence or not, the Mets bullpen is bound to suffer without their bearded comrade.

In response to this post, Zachary Rymer of Bleach Report wanted to know, “What about pitchers from other teams who got to face Dickey’s most recent opponent? Did they also benefit from a ‘knuckleball hangover’ effect in 2012? What about in 2010 and 2011?” After crunching some numbers, he concludes that the data are inconclusive. In any case, he argues…

…2012 is the key year in this discussion. Dickey’s knuckler was good in 2010 and 2011, but 2012 was the year it became the single most dangerous pitch in baseball. If ever there was a year that hitters should have been dealt a hangover by Dickey’s knuckler, it should have been last year.

Alas, it really only worked for Mets pitchers. Since other clubs didn’t clearly benefit from a hangover effect, you’re left with no choice but to tip your cap to Mets pitching coach Dan Warthen and the club’s other pitchers. They certainly deserve some credit.

Also in March of last year, Mike Axisa of’s Eye On Baseball observed, after noting a problem with sample size:

Big league managers have a tendency to do weird things like split up the lefties in their rotation or not use a fastball-slider reliever after a fastball-slider starter, but for the most part that stuff has little actual impact. Knuckleballers are a little different because they’re so unique, and it’s not shocking to see that regular non-knuckleball relievers tend to perform better when they follow someone like Dickey. The hitters are off-balance from one at-bat to the next. The day-after effect is a bit of a stretch though, especially since it only happened in a limited number of starts this year and not the previous two years. Still interesting though.

More recently (in November of last year), Chris Carruthers of BreakingBlue decided that assessing the widespread belief that “knuckleball pitchers can throw hitters off their game and leave them in a funk for days” (to the extent that some managers will require some players to sit things out for a while when a knuckleballer is on the mound) requires more precise analysis of the statistics than he typically sees.

Carruthers limits his investigation to the impact of Dickey, “the main knuckleballer in the game today.”

I decided to determine if there truly is an effect on pitchers’ statistics (ERA, WHIP, K%, BB%, HR%, and FIP) who follow Dickey in relief and the starters of the next game against the same team. I went through every game [2010-2013] that Dickey has pitched and recorded the stats (IP, TBF, H, ER, BB, K) of each reliever individually and the stats of the next starting pitcher, if the next game was against the same team. I did this for each season. I then took the pitchers’ stats for the whole year and subtracted their stats from their following-Dickey stats to have their stats [for the times] when they did not follow Dickey. I summed the stats for following Dickey and weighted each pitcher based on the batters he faced over the total batters faced after Dickey. I then calculated the rate stats from the total. This weight was then applied to the not-after-Dickey stats.

We’ll let Carruthers take you through the rest of his sabermetrics. What he concludes is that “starters after Dickey see an improvement across the board…. You may be disappointed with Dickey’s 2013, but he is still well worth his money.”

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