Yes, but be careful. If you have a bunch of free agents next year that you don't intend on signing, you may have under the minimum on your MLB team at the start of next season. If this is the case, the Sim will not let you demote him due to the minimum player rule (20). So, you will have to sign a free agent before Rule 5, assign that new player to your MLB team, then demote above referenced player before Rule 5. If you demote after Rule 5 draft (when spring training starts), you will get a demotion penalty assuming he has low patience.