Home Run Slump: Is It A-Rod or the Pitchers?

Alex Rodriguez of the New York Yankees is mired in a home run slump.  He last homered on June 11 and in the last 22 games he hit well, but just did not deliver a long ball.  Given that he's collecting a good number of base hits, it doesn't seem like there is anything wrong with his swing.

As a prolific home run hitter, PITCHf/x provides a nice sample of where A-Rod likes the ball in the the strike zone in order to take it deep:

Alex Rodriguez, pitch frequency, home runs, 2008-2011.The black box gives you an idea of where he likes pitches, down in the strike zone so he can get a solid upper cut swing at the pitch.  Lately, pitchers avoided that area of the zone:

Alex Rodriguez, pitch frequence June 12, 2011 through July 7, 2011.Rodriguez had a few pitches he might have hit out, but in general the approach against him was very good.  Notice this is what I call a septum heat map, where there is a nice separation between inside and outside pitches.  If I saw this for a single pitcher, my guess would be that he had a successful streak. In that light, Alex's hitting might be considered impressive.  He's taken what pitchers have given him and produced a high BA and high OBP.  If pitches start making mistakes against Alex, we should see him driving the ball again.