Greinke and BABIP

Zack Greinke of the Milwaukee Brewers will finish the season with a high BABIP.  He enters the action Wednesday night with a .325 mark, 13th highest among major league qualifiers.  Batting average on balls in play for a pitcher is often influenced by the defense behind the pitcher, and by luck.  In Greinke's case, he may share a great deal of responsibility for his high BABIP.

Take a look at Greinke's BABIP by the type of count, along with his percentile ranks:

Grienke 2011	BABIP	Percentile Rank
Hitter Counts	0.378	12%
Pitcher Counts	0.299	36%
Even Counts	0.320	30%

When Greinke is ahead or even in the count, his BABIP is poor but not terrible.  When he falls behind, however, hitters smash the ball.  Why?

When Zack gets ahead in the count, he uses his slider, which dives out of the strike zone:

Zack Greinke, pitch frequency in pitcher counts, 2011 season.When he falls behind in the count, he abandons the slider and throws fastballs in the strike zone:

Zack Greinke, pitch frequency in hitter counts, 2011 season.Greinke's not trying to fool batters, he's trying not to walk them.  A little history is important here.  When Zack played for the Royals, Brian Bannister pitched with him.  Bannister understood sabermetrics, including the idea that a pitcher was primarily responsible for walks, home runs and strikeouts.  If a pitcher minimized BB and HR, and maximized Ks, he then just needed to let the defense take care of the rest.

To Zack, a .378 BABIP in hitters counts means the opposition is making an out over 60% of the time.  That's much better than a walk, where the batter reaches base 100% of the time.  Sure, the Brewers could use a better defense behind him, but given his 15-6 record and 3.86 ERA. it appears Zack made the right choice.