There are lots of things we don't know about Mike Trout. But let's start with some things we do know. 1) He had quite possibly the best rookie season of all time in 2012, 2) he got even better his second year, becoming a more selective hitter and leading the league in walks 3) He had a massively underwhelming 2014, his batting average dropping 36 points, stealing half as many bases and his on base percentage falling 55 points, and 4) despite everything I mentioned in the last section he's still without a doubt the best player in the AL.
Think about that last point for a second. There's no one else in the league who could regress that much and still be that great. Of course, that also means people pay a lot less attention to it than they would anyone else. So should the Angels be concerned?
What I didn't mention in the first paragraph is that Trout's power numbers have increased, going from 27 to 36 homers and 97 to 111 RBI. Unfortunately, that's come at the expense of just about everything else. He made way less contact, his strikeouts spiking to a league leading 184 and his zone contact rate fell from .89% to .85%. In other words, he swung and missed at pitches in the strike zone four percent more often last year than 2013. While that may not seem like a lot, it comes out to about 124 pitches he wiffed on in 2014 he hit in 2013.
His concentration on power also has also affected what happens when he puts the ball in play. While going for more homers, 47.2% of balls he put in play were fly balls, up from 35.6% the year before. That caused his percentage of line drives to go down, dipping from 23 to 18.9%.
All of this is happening despite the fact that he saw more fastballs last year than in 2013. Last year, 62.4% of all the pitches he saw were fastballs, up from 60.5% in '13. I can't think of a single explanation for why this happened. It's possibly just a coincidence, but it doesn't matter whether it is or not, what matters is that he wasn't taking advantage of having more opportunities.
After looking at all this information, I'm sure Trout's skills aren't eroding. He's changed his mental approach. Which means he could change it at any time. So, to answer his question in the title, no, he's not getting worse. The best case scenario is a rich man's version of 2013. He's the five tool phenom he knew he could be. Anything's possible. The worst is pretty much last year. He decides he wants to be a power hitter and it comes at the expense of his hitting and base running. I hope he chooses the first route, but with Mike Trout, you can't go wrong either way.