Are knuckleballers more volatile?

For years, the Blue Jays have been also-rans in the AL East but splashed out this season turning prospects into established stars in the hope of reaching the World Series

Seven games in and the 2-5 start has the perennial doubts resurfacing, particularly as none of the much-vaunted starters has yet to pitch a seventh inning

Knuckleballer and 2012 NL Cy Young winner has had two outings. The first was memorable for a darting knuckleball leading to a BJ record of three passed balls. In the second, less movement led to home runs and a pretty dismal outcome. One suggestion has been that it is particularly early to draw any conclusions as knuckle ballers are by nature more prone to variability in their performance

One way of assessing this is to look at the pitcher’s game score – a swift method of comparing outings based on innings pitched, strikeouts, hits allowed etc.

Here is a graph depicting each of Dickeys career starts. Size of dot refers to innings pitched and colour denotes game outcome

dickey2

As can be seen, his first start this year was mediocre but the second was the worst since the 2008 season ( He only made one start in 2009)

Dickey appears to be a laid-back guy but is he by nature more volatile in performance? Of course, as he is now the only knuckleballer in the MLB little can be done to generalize but here is a box-plot comparing his 2012 starts with other leading pitchers: the group comprises the top three in last year’s CY Young voting for each league.
cyYoungGameScores

Not a lot to see there. Dickey’s variance was the second greatest but with no statistical significance perceived. Weaver managed two horrific outings, the better of which resulted in 8 earned runs with 10 outs

There is a Shiny App under development to view other pitchers, although there are some teething problems with 2013 data

Short URL: http://tinyurl.com/ko7oz69

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