Visiting Kris Medlen’s Curveball Tendencies

March 8, 2012 at 12:33 pm by David Lee under Atlanta Braves, Player Analysis, Statistical Analysis

Kris Medlen threw a few curveballs in his start Tuesday against the Nationals. While a third offering isn’t a huge deal for Medlen while he’s in the bullpen, it will be important if he gets back into a rotation some day, which I’m sure will happen at some point. His curve has never been above average, according to run values, but he has shown flashes.

In 2009, he threw it 19% of the time with a whiff rate of 12%, according to Brooks Baseball. However, he nearly abandoned it in 2010 when he made 14 starts for the Braves, throwing it just 9% of the time with a whiff rate of 7%. Compare that to Tommy Hanson’s curve, which he has thrown just 13% of the time over his career, but it breaks harder and results in a 14% whiff rate, as well as a 3% drop in line drive percentage from Medlen’s.

Medlen had potential with it in 2009 when he threw it at a decent rate. His home run rate was solid, he induced a ground ball here and there, he picked up a 24.5 K%, and he put up a 3.35 FIP as a rookie.

When he almost trashed it in 2010, he had similar independent numbers, just the opposite way. His FIP went up to 3.78, but his xFIP went down from 3.65 to 3.49. This was due to an increase in home runs to more than one per nine innings. You could say an innings increase had some effect, but leaning much more heavily toward a two-pitch repertoire likely had some say in the matter.

His swing and contact numbers also prove the change to fewer curves and more changeups. His swinging strike rate saw a slight decrease and he had fewer strikeouts in 2010, and he saw an increase in swinging strike percentage outside the zone by nearly 10%, and greater outside contact that year by 5%. So while he traded strikeouts by curves for contact on the changeup, he got weak contact on many of those pitches. It’s basically a different way to achieve a similar result (note: similar, not the same).

But perhaps the biggest change from Medlen’s 2009 to 2010 is something I haven’t mentioned yet: walks. Medlen is known as a tremendous control pitcher, posting just 27 walks in 120 innings at Double-A in 2008, and performing other similar feats during his minor league career. However, his walk rate jumped to 10.2% in 2009. Whether some of it had to do with nerves is not known. But it’s worth noting that after nearly ditching the curve in 2010, his walk rate dropped to 4.8%. I can’t help but feel there is a connection.

Basically, I waffled throughout this, but the point is to show Medlen went about his business in a different way between 2009 and 2010, and both ways were successful. One way – establishing a curveball as a reliable third offering – potentially leads to more strikeouts and walks (as it should). The other way – relying heavily on the changeup and essentially being a two-pitch pitcher – potentially leads to fewer strikeouts but weaker contact and fewer walks (as it should).

As I said in the opening, if and when Medlen becomes a starter again, I feel he should at least attempt to maintain his curve as a third offering, because while his changeup is a plus pitch, his stuff is not overwhelming three times through a big league lineup. Based on the numbers, I think it will be there when he needs it.

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