User blog comment:Xilinoc/Ch. 616 - Mimihagi-sama/@comment-5028409-20150220095412

Okay from my understanding of the chapter, this is what I predict is gonna happen;

MS translation says that Ukitake is gonna replace Mimihagi as the RIGHT HAND of the Soul King. If he's only becoming the right hand, who will be the new Soul King? I think the answer to that is Sousuke Aizen.

Aizen seemed to be close to achieving the level of existence of the Soul King as a transcendental being and considering the fact that the current SK and Mimihagi may be facing destruction, it makes sense that they have to be replace them with a new Soul King(Aizen) and Right hand(Ukitake) which is why Aizen is about to be released to take the Soul King's place which was his original goal.