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David Price's Curveball vs Slider

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When the 2010 season started there was little-to-no knowledge of David Price's curveball. Scouts raved about his slider and he used it more frequently than any other pitch outside of his 4-seam fastball. But in 2009 his slider was hit pretty hard, to the tune of -8.5 runs, and it lead to Price using his curveball more often than his change up the following season.

Price did not throw a single curveball in 2008 and only threw one 3.7% of the time in 2009. But in 2010 he threw his curveball 15.6% of the time and only threw his slider 4.9% of the time. His slider was worth +1.2 runs in limited duty and his curveball was worth +1.5 runs as his favorite off-speed pitch.

But in 2011 Price's curveball had the misfortune of running into too much hard contact and was worth -5.7 runs while his slider was worth +1.2 runs. His curveball had the highest line drive rate on balls in play of any of his pitches at 23.73% while his slider was by far the lowest at 9.76%.

He finished the 2011 season using his slider slightly more than his curveball but that wasn't the case until a change in approach after his August 7th start when his results based stats were at their highest since April.

From Opening Day start on April 1st to his start on August 7th (my birthday) he threw his curveball 10.4% of the time and his slider only 6.8% of the time. At that point in the season Price was sporting a 3.89 ERA in 159.2 innings of work with a 0.79 GB/FB ratio and a 1.01 HR/9. A valuable line but not the Price that fans had grown accustomed to seeing.

After his August 7th start his approach changed to where he was using his curveball only 6% of the time and his slider went up to 11.8%. Decreasing the amount of times he threw the curveball also meant an increase in his change up usage, up to 12.4% from 11.1%, and his change up was his best off-speed offering at +10.4 runs. His slider also saw an increase in velocity from 88.5 mph to 90.0 mph.

Price's results after his August 7th start until the end of the season when he ditched the curveball in favor of his slider were a 2.96 ERA in 76 innings pitched with a 0.91 GB/FB ratio and a 0.83 HR/9. And it's not as if he faced easier competition. In those 10 starts he faced the Yankees twice, the Red Sox twice, the Blue Jays twice, and the Tigers and Rangers once.

For the entire season, Price's slider saw the highest percentage of ground balls at 11.32%, more than his 95.5 mph sinker, and he allowed only one homerun while throwing his slider against three while throwing his curveball.

This is not to say that Price should completely ditch the curveball. The pitch has its uses. He threw it 83 times as the first pitch to a right-handed batter and received the second lowest percentage of swings of any of the pitches he threw in a 0-0 count to right-handers. In those 0-0 counts his curveball was a called first strike 45.78% of the time against 38.55% called balls. And when the batter did swing they whiffed 30.77% of the time and fouled the pitch off 38.46% of the time.

The first pitch sample sizes I am playing with are a bit small but I am a believer in a pitcher who can throw his curveball for a first pitch strike and I believe Price has the ability to do so. I also believe, from his 2011 data, that it is pretty evident that when Price is throwing his curveball less, thus throwing his slider and change up more, that he has the chance to be a more dominant pitcher.

Here's to hoping that his approach after my birthday is the same approach he brings into the 2012 season.