The Evolution of Clay Buchholz's Slider

Lined up to be third in the Red Sox' 2011 rotation, Clay Buchholz has finally established himself as a major league starting pitcher.  He's gone through his fair share of highs and lows since his first call-up in 2007, including a no-hitter in his second career start and a world of struggles that plagued his 2008 season.  While his low-mid 90s heater, hard 12-6 curve and straight change have been staples in his repertoire for the majority of his career, his slider has evolved quite a bit.

What's causing this?  I did a similar sort of analysis with Joba Chamberlain's slider last year, and I concluded that the decrease of movement on the pitch was due to a lapse in command.  In Buchholz's case, it is a conscious decision: first, it would be impossible for a pitch to increase by at least 7 mph and lose that much movement "by accident".  

Second, we have an awesome article by Brian MacPherson from a May 2010 issue of the Providence Journal.  There are three things from the article that I found extremely telling.  Here's Buchholz talking in the middle of last season about the velocity increase and how he was actively trying to throw the pitch harder:

I tried to do it last year, but it didn't turn out the way (I wanted).  There were a couple of games when it was hard, and there were a couple of games when it was 84 or 85.  It was this year in spring training that I made a conscious effort to throw it the way I wanted to throw it, the way I wanted it to look, and it's gotten better.

Another thing that caught my eye was a quote from MacPherson regarding Buchholz's slider grip and his assistance from teammate Jon Lester:

"As part of the evolution of his slider, Buchholz saught the guidance of Lester and adapted a little bit of Lester's cutter grip into his slider grip.  Like Lester, Buchholz can throw his slider with less break to get a strike and with more break  - he puts a little more pressure on his middle finger to make the ball move - to get a swing and miss out of the strike zone."  

I would have no problem with calling the current incarnation of Buchholz's breaking pitch a cutter, especially given the fact that he's adapted Lester's cutter grip.  Buchholz himself has said it's "both" a cutter and a slider, and that he puts some extra pressure on his middle finger to apply more movement when necessary.    

"The delivery of it - and the execution of it - is a little bit more of a fastball mindset.  It does create a little bit more power, a little bit later action, a smaller break, but it's easier to control and easier to get into the strike zone.  He's gone from what was more of a true slider and what would be more hit-and-miss prior to the midpoint of last year to a pitch that he feels more is just a variation off a fastball."

        
Observations:

• The new cutter gives Buchholz another pitch to throw against left-handed hitters.  In 2010, he actually threw a greater percentage of cutter/sliders to lefties than he did to righties.  
• The cutter isn't necessarily in the strike zone more than the slider was, but Buchholz does appear to have more control over it, given the increase chase% and decreased ball%.
• The slider used to have a really high watch rate, which means that batters weren't prepared to swing when it was in the zone (curves are typically the pitch with the highest watch%).  Now, batters are swinging at it much more when it's in the zone.
• Fewer whiffs, but that may not be that big of a deal given the increase of swings out of the strike zone.