I don't know how they factor defensive metrics, but I can't look at errors and think it's the end all of stats. Let's say I'm playing SS. I'm 62 and not very quick. I might never make an error unless they hit the ball right at me because I have no range. CC on the other hand, is going to dive for balls I have no business getting to, but he's going to make a few errors because he's getting to stuff most of us can't get to. Plus, there's fielding errors, throwing errors, and mental errors. Maybe they need to split those up in the stats. In short, CC has better defense than me, despite my idiot little league coach who put me there.