[uruguru]

ok, I think I figured this out already!

I am playing with fielding ratings set at "current season". My sim started at 1962 and Hank Aaron in every season afterwards NEVER played 2B in the real world in any of those seasons.

If you start a 1962 season with fielding set to current season, Aaron's experience at 2B is set to 0 -- which means the AI will never attempt to play there.

But if you then go to League Settings and set fielding to "entire career", it will re-rate Aaron at 2B... because he is then rated well enough to play 2B... and it gives him 200 experience at the position.

ok, great. You can play him at 2B with "entire career" fielding ratings. that's legit..

But if you go back to league settings and change the fielding back to "current season", it properly adjusts his ratings back down (so that he's a terrible 2B).... BUT IT LEAVES HIM WITH 200 EXPERIENCE AT THE POSITION.

And then that signals to the AI that Hank Aaron can be played at 2B, even if he's terrible at it. But he's such a good hitter, his overall rating at 2B will be better than other 2B.

So, I think this is a problem with fielding experience not resetting properly when you switch how your fielding ratings are determined. And I suspect that this is also related to the recent change that allows players to "remember" their fielding experience even when they recalc to a new historical season.

I honestly think this is what is happening. I'll submit a bug report.