Check out the evolution of the Dodgers' Clayton Kershaw from a fastball/curveball pitcher to a fastball/slider pitcher.
2008
In 22 games (21 starts) in 2008, Kershaw was 5-5 with a 4.26 ERA and a 1.495 WHIP.
Kershaw in 2008 had a .264 batting average against
Kershaw threw 1891 pitches in 2008
Fastball - 68.0% (1286 pitches) - .291
Change Up - 4.5% (85) - .167
Curveball - 21.6% (408) - .153
Slider - 0.3% (6) .500
Cutter - 0.1% (1) .000
2009
In 31 games (30 starts) in 2009, Kershaw was 8-8 with a 2.79 ERA and a 1.228 WHIP.
Kershaw in 2009 had a .206 batting average against
He threw 3259 pitches in 2009
Fastball - 66.5% (2168 pitches) - .216
Change Up - 4.0% (130) - .355
Curveball – 16.8% (546) - .126
Slider – 6.9% (225) .143
Cutter - 0.6% (20) .000
2010
In 32 games (32 starts) in 2010, Kershaw was 13-10 with a 2.91 ERA and a 1.179 WHIP.
Kershaw in 2010 had a .214 batting average against
He threw 3390 pitches in 2010
Fastball – 70.5% (2390 pitches) - .243
Change Up – 1.3% (45) - .250
Curveball – 6.8% (229) - .290
Slider – 19.5% (662) .108
Cutter - 0.5% (16) .000
2011
In 32 games (32 starts) in 2011, Kershaw is 20-5 with a 2.27 ERA and a 0.987 WHIP.
Kershaw in 2011 has a .208 batting average against
He has thrown 3375 pitches in 2011
Fastball – 65.3% (2205 pitches) - .272
Change Up – 3.6% (122) - .059
Curveball – 5.2% (176) - .146
Slider – 24.1% (813) .117
Cutter – not thrown
The change in Kershaw has been both significant and successful.