Vlad's numbers are purely the product of poor swing decisions. He has the talent to put the bat on any ball in or near the strike zone and hit it harder than most. As a result, his brain tells him to swing at pitches that he shouldn't be swinging at. Sure he can still make harder contact on that pitch 2 or 3 inches outside, or inside, but he's putting those balls in play when he should be taking them for balls. Look at his walk rate plummetting, he's getting every opportunity to put himself at 1B via the walk and just wont do it because there's something in his brain that tells him he has to swing at something he can make contact with.
The secondary problem is that he keeps getting just enough positive results on those crappy swing decisions that he keeps doing it, even though it's really not all that positive. The HR he hit on that pitch in the last game of the Mets series... way up and in at the upper and innermost corner of the strike zone. he shouldnt have swung at that pitch. Yes, he hit a HR this time, but how mnay pitches in that area has he actually done damage on this season or his career? not many. That one positive result is going to keep his brain swinging at that crap and the next 25 times he does, the results will probably not be good.