Aubrey Huff of the San Francisco Giants saw his batting averages drop in 2011 compared to his fine 2010 season. His BA dropped about 45 points, his OBP about 90 points, and his slugging percentage fell about 125 points. His weighted on-base average (wOBA) sums up the drop, going from .385 in 2010 to .295 this season. The difference appears to lie in his swing and contact statistics. Huff is swinging more and missing more in 2011.
In 2010, Huff swung at pitches that were up and in the middle of the strike zone:
That's a good place for him to swing, because that's where he tends to make contact:
In 2011, he's swinging at lower pitches:
Pitchers are throwing him more sinkers this season, and he seems to be chasing them. That chase hurts him:
Those swings on sinkers are usually misses, putting him in a hole or out. His contract rate on pitches up in the zone remains high. He needs to let those low pitches go for balls.
Note that in 2008 and 2009, he exhibited a similar rise and decline. The 2008 season was a great one for him, posting a wOBA of .386. That dropped to .305 in 2009. Once again, the difference between the two seasons was Huff chasing low pitches in 2009 that he didn't chase in 2008.