Of third basemen, corner outfielders, and first basemen with the big league club I trust Mauer the most to play consistently good defense and offense, more than Arcia, Plouffe, Willingham, Parmelee, or Colabello. The Twins started this season with Mauer at first presumably because Sano is/was the third basemen of the future, and Mauer had played first in the past, it was an easy transition with no real immediate candidates for the position coming up through the minors. No one knows what the future holds for Sano. He may come out of TJ surgery just like the kid from "The Rookie" and magically able to throw 100 mph, but we do know is best case scenario, he comes back ready to play for spring training 2015, and maybe not until mid way through the season, and maybe (though highly unlikely) never plays again. He wasn't a lock to come up to the bigs at any point this season, and now being out of baseball for 6 - 18 months, he's going to need to ease back into things. I'd look for Sano to be major league ready in 2016. Now the question becomes would you rather have Colabello/Parmellee at first than Plouffe at third? Or Colabello/Parmellee at first than Willingham in LF or Arcia in RF. i think Mauer could become a defensive upgrade over all of the other options, I don't trust Colabello/Parmellee to hit well enough over a season to justify the shift. What if Mauer negotiated that the only way he would get out from behind the plate is if he went to first?