Is it possible to assign a ML player coming off the 60 day DL to AAA for awhile without taking a ratings hit? I have two rookies who suffered major injuries that they recovered from over the offseason, but they are no longer my best option in the majors.  However, I 'm worried that if I move them back to AAA (both have options remaining), they will take a further hit that will outweigh any potential growth.

Any demotion incurs the possibility of a ratings hit.

Have you started your new season yet? If the regular season has not started you can demote them without any penalty.

assign them before spring training starts and you will not get a penalty