Has he lost some velocity this year too? Perhaps I never pay enough attention to the radar guns, but I seem to remember some times where he'll top out at 93 mph in a game, rather than the 96 that we've seen previously. And if this is so, has it been a slow decline or is it just this year?
He is pitching to contact more this year than any other, so it stands to reason to stay away from trying to strike out guys with high velocity and trying to get them to ground out. His location has been off and that pretty much makes a 93 mph sinker very hittable. A 93 mph sinker at the knees on the corners is unhittable or if they manage to put the bat on it, it will be a do nothing ground out.
Lack of location on the fastball (consistently), lack of control of the curveball and just no confidence on the changeup pretty much makes him an average major league pitcher. Sometimes he'll win, sometimes he won't.
I suspect he'll get it back sometime, but right now it's just frustrating to watch him be so average.