Piggybacking off the previous post, Fangraphs says Mauer is the 3rd best out of 28 first baseman for 500 innings in the field. Eyeball test agrees, and even if Mauer is slipping ever so slightly, he is still one of the best at the position across MLB. Without Mauer at first base, all the other infielders drop a notch, too. I also think continuity into 2019 is an important factor with this one.