More or less, he may not be trying to do it, but a whole mess of balls he had been beating into the ground are now liners and flies. He's hitting like it is 2009.

Average Flyball/Line Drive, Goundball, and overall Exit Velocity according to statcast.

2015: avg FB/LD EV 95.0 MPH; avg GB EV 89.6 MPH; avg EV 92.1 MPH

2016: avg FB/LD EV 95.8 MPH; avg GB EV 93.0 MPH; avg EV 93.7 MPH

2017: avg FB/LD EV 98.1 MPH; avg GB EV 85.6 MPH; avg EV 91.5 MPH

So what appears to be happening is that he is sacrificing a little bit of overall "hard contact" for a better launch angle and better contact when he gets the ball in the air. Obviously its a very good tradeoff so far - that's legit elite contact on FB/LD, it would have ranked 6th in MLB last year.