I could understand that Grimmjow having his arm cut off for his behavior in a previous episode but how come he didn't heal it back?
I can't fully remember if it was just decapitated or "evaporated" but having great power and all, why not see the arrancar medic like yammy did and get it replaced?

sidenote- I'm in ditto with Harima Kenji's theory for what's to come but I don't think Aizen would go to such a length to take Orhime just for Grimmjow's recovery