For purposes of this list, we define low ball as any pitch that located below a line 6 inches above the bottom of the PitchFX strike zone, even if it was outside of the actual strike zone (for example, balls in the dirt or pitches way inside are included if they were below the line).
One thing stands out: 9 of the top 25 worst hitters of low pitches this season are catchers. Is this due to catchers struggling to bend down to hit the low pitch as a result of knee issues? Hideki Matsui (OAK) also makes the current list and his knee issues are well documented.
At the end of 2010, only 4 catchers made the list (min. 100 plate appearances decided on a low pitch). But if we take all data from 2009 to the present with a minimum of 150 plate appearances decided on a low pitch, 10 catchers are in the Top 25. It's possible that with last season being the "Year of the Pitcher," more non-catchers flooded the top of this list, with offense down across the board. Or it could simply be that catchers overall tend to be among the weaker hitters in the league. Or maybe 2010 was just be an outlier.
As much as I'd like to speculate that catchers have trouble hitting low pitches as a result of knee problems, the current 2011 list is most likely a product of a small sample size. Nonetheless, we'll keep an eye on how the list changes throughout the season.