He's having a kind of fascinating season, with a .327/.412/.492 line that looks pretty distinctly Mauer-ian, except with 20+ additional points of SLG. Whether an increased strikeout rate is a sign of trouble in the future or not,* it's clear that Mauer has been:

a)selling out a bit for power
b)actually succeeding at hitting for more power

What's odd is that we're not really looking at a big homerun spike. If he hits fifteen, that would be his 2nd highest total of his career, but not enough for us to say "oh, that's something new". 2009 was a clear oddity in the power department, but I maintain that the move to the new park has done more to keep his liners in the building than anything structural about his game. About 34% of his hits have gone for extra bases this season, higher than his lifetime mark of 29%.

It'd be rather cool if he settles into a synthesis whereby this power increase sticks, but the strikeouts return to normal levels and we have the same old Mauer spraying linedrives all over the park, but with isoP numbers more like 20009 than any year before or since.

*added strikeouts and homers has been referred to as the development of "old player skillset" but that doesn't quite describe Mauer. I'm a bit more comfortable finding signs of decline in new platoon issues, which Mauer isn't exhibiting, actually hitting LHP better this year. Justin Morneau's .282/.320/.338 line against lefties is what it looks like for a player getting old fast.