In fairness, it seems his power has jumped a bit this year to closer to what his frame says he should support. He is not benefitting from a fluky BABIP (.317 the past 2 years, .321 this year). The other thing that seems to have happened is his aggressive approach has led to a cut back in K% so far. In other words, he seems to have a better sense of what he does well (he's a fast guy without an ability to draw walks, so going deep into counts does not usually pay off). The only other time he had this low a K rate was during his first call up, which also was his best power month (or one of).
edit - the complete absence of pop outs and the jump in liners looks flukey.