Not the same player, obviously, but Danny Espinosa went .264/.375/.460 as a 22-year old in Potomac and .262/.334/.464 the next year in Harrisburg.
I think it's a quantum leap forward when the pitchers start being able to locate all their pitches within the strike zone. It's one thing lay off balls outside the strike zone, it's another thing to be selective within the strike zone. Since he seems to make pretty good contact, maybe he's simply making contact earlier in counts, now that the pitchers are throwing more inside the zone?
Either way, I'm not worried as long as he continues to make good contact and hit for the same power. That means he's still being selective and hitting the strikes he wants to hit, rather than making weak contact on pitcher's pitches.