SABR

Sheppard: Tracking R.A. Dickey's knuckleball

From Drew Sheppard at FanGraphs on June 18, 2013:

You all know the R.A. Dickey story by now. Journeyman major leaguer reinvents himself as a knuckleball thrower in his 30s, then refines the pitch to become one of the better starting pitchers in baseball, culminating with his selection as the National League Cy Young Award winner last year. The knuckleball is always a fascinating pitch, and Dickey is a fascinating guy, so there has been no shortage of media attention focused his direction.

While I was not working here at FanGraphs last year, I could not resist taking a belated look at some of Dickey’s dominating knuckleballs from that 2012 season. I’ve selected three particularly impressive pitches from that campaign and used an effect known as StroMotion to help track their movement.

While traditional pitches create movement through spin induced by grip and arm action (exceptional curveballs have been measured at 2,500-3,000 revolutions per minute) creating high pressure zones that deflect the ball in the opposite direction, the key to the unique movement of the knuckleball is a near complete lack of spin. The ideal knuckleball makes just 1 to 1.5 rotations (~150 RPM) between release and home plate, causing the drag on the ball to shift significantly mid-flight as the leading seam of the ball rotates slightly, resulting in unpredictable and uniquely sudden movement.

Read the full article here: http://www.fangraphs.com/blogs/tracking-r-a-dickeys-knuckleball/

This page was last updated June 18, 2013 at 1:30 pm MST.

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