In terms of percentages, Trout already lays off the high fastball.
This is from Fangraphs:
In fact, I’m not even going to cite numbers. I’m looking at numbers, here on my own laptop, but I’m not going to write them. Numbers are ugly to read and oftentimes they’re unnecessary. I can just give you some true statements, based on PITCHf/x.
Against elevated pitches out of the zone, Trout finished with one of the lowest swing rates in baseball.
Against elevated pitches in the zone, Trout finished with one of the lowest swing rates in baseball.
Looking at the same things, but with two strikes, Trout finished with some of the lowest swing rates in baseball.