Why is Brandon Wood such a terrible hitter? Since the start of the 2008 season, he posted a .169/.200/.257 slash line. That might be okay for a pitcher, but a major league third baseman can't survive with such low averages. Part of the problem is that Wood gives away a large part of the plate.
That's a huge area where he is taking pitches that have almost no chance to being called balls. One reason he may take there is that he often swings and misses those pitches:
Note that little green donut hole on the inside half of the plate? That's Wood's hot zone:
So he can't hit balls on the outside part of the plate, so he takes those pitches hoping to get a ball down and in. His taking strikes leads to another problem as well:
Look how far off the plate a pitcher needs to throw before the umpire gives Wood the ball call. The dotted line represents the area of uncertainty, yet outside of that line Wood is only getting 50% of the calls. Wood gave away the outside half of the plate, and the pitchers and umpires give him no benefit of the doubt. Until Wood takes back the outside part of the plate, and shows he knows the difference between a ball and a strike, he won't get those calls.
Of course, it just may be that down and in is the only place where he can be successful when he swings. If that's the case, he won't be in the majors much longer.