Defense is also a team activity unlike batting. There are multiple individuals involved in the production of almost all outs, especially for Braun. For instance, his usual first basemen is fairly short. If it was someone like Derrek Lee and his rating increased significantly would he be a better fielder?

The fielder's position are not calculated either. You've seen Yost's shifts. He loves them. When a ball is hit in a zone, the rating doesn't consider whether it is reasonable or not.

And like all science, the calculations are built on raw data. That's a guy looking at videotapes. How good is that? Its unknown. The Brewers, including Braun can have their ratings radically affected by the competence of the individual or how well he correlates to others doing the rating. The Brewers could be affected by camera positions or lack of cameras. I've read that the two sources of raw data, BIS and STATS, don't match very well.

I'd be interested in seeing calculations done when Braun's overthrows that weren't hurried were taken out.

And think about working backwards (or in my mind forwards) and looking at team defensive performance. Using runs allowed, the Brewers are about middle of the NL. Supposedly Prince isn't very good, Hardy is mediocre without much range, Ricky is poor, Billy was bad, Jenks was average to above average and you could say the same thing about Corey. Oh, and everybody will tell you that Johnny was really bad. That's the description of a bad defense. That defense and pitching and luck I suppose are the elements that determine runs allowed. With a bad defense, the pitching would have to be pretty good.

Is Braun a bad fielder? Maybe yes, maybe no. A lot depends on how you define it and how you measure it.