I somewhat agree with last year's shut down, but I also agree other than that, he has been babied too much. I don't think that's the reason he might be underperforming (if you can call it that).
He sometimes looks frustrated in the mound, his team commits a lot of errors when his pitching and they don't bat at all for him. Every time I watch him pitch he seems to get a lot of bad breaks, but BABIP doesn't support that theory.
I really think he can be the best in the league, they gotta stop babying him and he has to go on a little run to gain some confidence.