Which means it's possible for Phantom Champion Z to take place in Johto.
Mostly because I'm pretty sure by June/July of this year Japan will be to the second Battle Frontier arc when Ash is attempting to take on the Frontier Brains from Platinum.
I don't have any proof for this, of course, I suppose this is just my opinion and what I think will happen.
Basically... I'm just guestimating here. ^_^'