There is nothing stopping them, would just look ridiculous to say a bloke is being managed & then play him as an emergencyIt doesn't ring true. Why would the AFL seek to control how a player is used? Shouldn't be anything stopping a "managed" player from being named as an emergency if he's the best insurance for his replacement.
Geelong did this frequently through 2011 on their way to the flag, and the player was listed as "rested". The new terminology "managed" is less suggestive to the public that the club is playing funnybuggers.