Over the weekend R.J. Anderson, Zach Sanders and others tweeted about Tommy Hunter‘s curveball. R.J. noted that Hunter’s curve was way up in the zone during Hunter’s start on Saturday. I was not watching the game, but I thought it was an interesting observation. I pulled up the pitchf/x data for the start and they were right:
His curveballs were very high: most in the upper half of or above the zone. Those curves got him a good number of called strikes, a handful of whiffs, and a couple balls in play (all outs).
Next I wanted to see whether his curves were always that high and how they compared curves as a whole. So I plotted a histogram of the height of all of his curves (his one start in 2010, a couple from 2008 and 19 from last year) and those for all curves in the pitchf/x data.
Hunter’s curves are, on average, a good six inches higher than the average pitcher’s. While curves as a whole peak in the bottom third of the zone and there are a good fraction below the zone, Hunter’s curves peak above the middle of the zone and a good number spill out above the zone.
Do all these high curves hurt Hunter? It doesn’t seem so. He throws the curve a lot, over 25% of the time, and by linear weights the pitch it is a very good pitch. Digging into why that is we can compare some of its components to Harry Pavlidis’ benchmarks for the curve:
Swing = swing rate (swings/pitches)
Whiff = whiff rate (misses/swings), includes foul tips
IWZ = rate of pitches thrown within a “wide” strike zone
Chase = swing rate outside of the wide zone
Watch = take rate inside of the wide zone (inverse of swing rate)
nkSLG = non-K slugging, or SLGCON
GB% = rate of balls in play tagged by MLBAM stringers as grounders
LD% = line drives
FB% = outfield fly balls
PU% = infield fly balls
You can see the big difference here is that Hunter’s curve is in the zone more often, swung at much more often, and not watched (taken in the zone) as much, and, because the pitch is so high in the zone, it gets very few grounders but lots of pop-ups. The result is a much smaller slugging on contacted curves. That is on just 95 curves put in play. I don’t know whether Hunter can maintain such a low slugging on his contacted curves or continue getting one in five to be popped up, but so far his high curve has worked well for him. It is an interesting pitch: while the average curve gets lots of called strikes and grounders, Hunter’s gets many more swings and then flyballs.