User blog comment:Soulreaper1234/Urahara says Fusion Aizen says Subdue/@comment-1248963-20100510202209

Yeah, that's kinda what I was thinking, that the Hogyoku is trying to take over Aizen's body to get a body of its own. Could the Hogyoku become the new enemy for the upcoming arcs? Now that would be insane.

I believe Aizen is being too careless here allowing the Hogyoku to act freely on his body, thinking that he has "subdued" it, but forgetting the fact he himself stated previously, that the orb has a will of its own.