User blog comment:Caesarea37/Aizen and the current state of his Zanpakutō/@comment-1393830-20130319190356/@comment-4822693-20130321232308

I find it hard to believe that he simply lost track of time. The conversation probably went like this: Juha "Aizen want to join the us and kill the soul king." Aizen "No I'm just going to wait it out. All of you are going to get killed by Ichigo. In 20,000 years I'll be the only transcendent entity left and then I'll take over the universe." Juha "Well you're a coward. I guess I'll just go do it myself."

Besides in Chapter 514, page 12 He says "Impossible we should still have time- ...I see... Aizen Sousuke. This is his doing...In the few minutes we were in contact, he managed to disrupt my senses." From this it is clear to see that Aizen purposefully used his powers to affect Juha's sense of time. The only power we know to be able to do this is Aizen's zanpakuto.

Other people might disagree, but the conclusion that I have drawn from this is that Aizen's asauchi created base was destroyed. Therefore he is not able to materialize a sword. However as we have seen with Ichigo and Isshin, who both have lost their powers, the innate "soul abilities" will always remain. When Ichigo regained his powers he still had Zangetsu for a sword. Since Aizen still retained some of his powers in the form of spiritual energy he is still able to use his innate power. It's obviously weaker than before, because he doesn't have a zanpakuto to channel it, but he still has his illusion powers. This is also supported by the battles with the Stern Ritters, who had limited unique powers. If they had been shinigami and possessed zanpakuto's those powers would have been more powerfully developed.