[wuttang]

I can see batting and pitching potential, especially when I go into the editor, but couldn't find any Fielding related Potential.
How do players improve defensively? Do they all improve at the same rate or is there no change at all?
I can see how speed, range, arm might be set and not improve, but what about Error rate or infield double play rate?
I read Position rating grows as the player plays that position more and more. does it grow the same for all players?
I'm curious is to other ratings such as stealing, baserunning, bunting which I could see players improving but have no potential rating.

thank you for any info available