I'm not 100% certain on this, but Parson by being a 3rd year RFA takes him out of the Gilbert Arenas rule if I'm correct. Meaning that teams can offer him any amount they can afford. To contrast this, if Parsons does fall under the Gilbert Arenas rule, then the max money he can get is about 4yr/$40mil(5/5/15/15). Meaning there is some financial incentive for the Rockets to make him a RFA and then re-sign him for 4yr/$40mil. Assuming they feel he can get much more than that in 2015.
But without the Arenas restriction, Parsons can be offered max if he enters RFA, which doesn't really help the Rockets at all. Especially if Fegan gets some other team with his big name players to make a ludicrous offer. Boozer, while not exactly the same situation, was the perfect example of what can happen when the team relinquish their rights to a player.