OK, I demoted my 24 year old OF with Patience of 70 and Temper of 64.  He wasn't getting it done and I picked up a veteran bat who was pretty good for me a few years ago.  My 24 year old lost 1 pt in Contact, vR and Eye.  He will come back up when rosters expand (we are at the ASG break right now).  Does a 24 year old with pretty good patience pick up those lost pts?  I know they are probably insignificant but I was hoping I could slide him by.

Sometimes.   Not necessarily due to promotion but just normal development. 

I'd make a big bet there is no record kept in a player's data for points lost due to demotion.  And a bigger bet that, if that data is stored, those points can not be earned back if certain things happen.  They are gone forever.

That doesn't mean new points can't be earned.  Normal development seems to continue. So if he's in his first 3, maybe 4 seasons, he might still pick up a few points. But those are his typical development points.  My bet is they have nothing to do with making up lost points.

I demoted a guy from triple a to double a for playoffs and his ratings went up, I have never seen anything like that before have you guys?

It's rare but it happens.

Just demoted him at a development cycle.  Fortunately he didn't get the demotion hit.