My conspiracy theory is that his struggles are the result of him trying to adjust and failing. Mauer has always been a patient hitter that lets the ball get deep on him and then slashes it the other way, but I remember a couple quotes and some in game announcer chatter about him attempting to pull the ball a lot more and change his approach. It seems like he got himself way out of whack with that, add learning a new position on the fly, being absurdly unlucky on line drives going right at people, coming back from a concussion, dealing with new wear and tear, and dealing with the resurgence of the blame Mauer crowd and I think it has snowballed. His last 3 big hits have been classic Mauer, 2 doubles and a single slashed the other way so maybe he is going back to the old approach.