Mike Trout
first 15 games this year:
.323/.380/.646
16 SO in 71 PA
5 HR, 11 RBI
.364 BABIP
next 15 games:
.273/.388/.436
23 SO in 67 PA
1 HR, 8 RBI
.438 BABIP
That last number tells me his hitting zone is getting smaller. He's only swinging at the best pitches in the strike zone. The pitchers are killing him on the outside corner. He's letting those pitches go by for strikes. He's still getting his share of walks, though.