Has anyone looked into how/if position changes affect position players? It seems to me that any time I've changed a players position at the ML level it's set them back the first season on offense. In some instances a very significant drop in offensive productivity. Just curious if it's a coincidence or not.

I'm pretty sure it's a coincidence. Some of the people who've been playing longer than me can probably give a more evidence-based answer, but everything I've read tells me that the position a guy plays doesn't affect his hitting. Offensive performance is based on offensive ratings, and isn't affected by fielding.

Two theories:

1.  We see what we think should be true.

2.  We remember when something goes wrong. 

Basically, one would think a guy adjusting to a new position might struggle at the plate a little because he's taking extra grounders instead of extra swings.  He's carrying a bad play in the field to the plate.   Something like that.     Or a guy switches positions and declines at the plate.   We notice it.  A guy switches positions and remains the same or, better yet, hits better.    Remaining the same isn't noteworthy and getting better just means he's finally hitting like he should.   For every 1 "Is he overperforming?" sitemail I get, I get 20 "Why is this guy underperforming?" sitemails. 

Rule number one of statistics:  Correlation does not equal causation.