Well, first let's see if what our eyes tell us about his stuff is true. Is he throwing the same pitches, and at the same velocity and tendencies?
You all feel it. Something is different. Something has changed in the way Clayton Kershaw has pitched. His numbers are still there. The strikeouts, the walk rate, the velocity, the "stuff", the "Public Enemy Number One". But it just feels different this time. Like that eerie feeling the comedic relief actor feels about halfway through the horror flick. Everything seems fine, but you just know something is out of place. So, what is it?
Pitch F/x says Kershaw over his career: Fastball 93.3mph (68.4%), Slider 82.8mph (15.7%), Curveball 73.3mph (11.5%), Changeup 83.5mph (3.5%).
In 2012 to date: Fastball 93.0mph (60.9%), Slider 85.3mph (24.0%), Curveball 74.0mph (9.9%), Changeup 84.0mph (4.9%).
But remember he didn't throw a slider until 2010, so those numbers are a bit misleading. What we can take away from the data is that he's throwing fewer fastballs than last year, though not because of a lack of velocity. His slider percentage is identical as last year (24.0 his year vs. 24.6% last year), but he's throwing his curveball (5.4% in 2011) and changeup (3.7% last year) a little more.
The main thing that's different: 2011 Strikes:Balls (64.1%:35.9%), 2012 Strikes:Balls (65.3%:34.7%). He's throwing as many strikes as last year. But his 2011 O-Contact% (that is, the number of pitches out of the strike zone that hitters make contact with) was 55.4% while the league average was 64.7% (Kershaw career 59.4%). In 2012, his O-Contact% is 60.2% (league average 64.3%).
So in summary, if it seems like Kershaw hasn't been as dominant as last year even if his "stuff" seems just as good, we can see that hitters are making contact with pitches out of the zone more than ever.