Why is this your only shot at cap space for a while? It's not like you have to use it this free agency, or am I missing something there.
2014 seems like a much more reasonable time to go after a center with Cousins, Monroe, Bogut, Gortat, Varejao, and Okafor out there.
Also, let's say Lillard wants out of his deal early for a bigger contract. To ensure he stays in Portland long-term, the Blazers could do that next summer, but if they had Hibbert's contract on the books, that'd put them way over the luxury tax and probably mean losing Aldridge.