You have to decide how may to keep before addressing this in any detail. My thoughts on order of value:
Ed Davis - young, lots of upside and he play defense (you know, the thing in your zone). He and Demar are the closest to untouchable the Raps have
Amir Johnson - great energy, however, could easily be nudged down the list because he and Ed may end up at the same spot. Despite the overlap he has a lot of team-friendly intangibles that are good even if he doesn't start.
Andrea - a distant 3rd. Has the polish and offensive tools but it is time for him to stop being the perennial future of the team.
Reggie - at the right price, I'd put him as high as 2.
Alexis - still haven't seen enough, but shows good confidence on the floor
Joey Dorsey - may be he's hit his ceiling?
Solomon Alabi - early to say either way but he isn't going to be a Mozgov-calibre dealbreaker on the trade market. He'll have time to develop in TO or Erie.
Pare the list down according to what we need.
Ajinca - still young