It's one thing to move Trout to LF, because you have a Bourjesus in CF.
It's totally another to move Trout to LF because you have nobody, and you want to put a replacement player in CF.
And heck, I've used the LF is a lot less stressful, and helps to prevent injuries for Trout. But again, it's easier to make that argument when you have a quality defensive CFer. And we don't.