If it was up to me he would be up here tomorrow. But if you go by the rhetoric and pattern of this front office, they will probably keep him there for a couple months, unless he does to AAA for like a month striaght what he is doing to AA, or better.
Again, he needs to exceed the expectations of the club at each level. Until he does that, he isn't getting called up. So who knows. But if I were betting, September is my call.