Per Fangraphs, Mauer, this year, is +1 DRS on defense, with a +2.1 UZR and +6.1 UZR/150. 26 1Bs have 550 or more innings at 1B. Overall, Mauer is ranked 2nd for AL 1Bs and 3rd for MLB 1Bs. So, compared to other 1Bs, Mauer is a top notch defender. One complaint I have with Molitor, is he needs to play Mauer at 1B more. https://www.fangraphs.com/leaders.aspx?pos=1b&stats=fld&lg=all&qual=550&type=1&season=2018&month=0&season1=2018&ind=0&team=0&rost=0&age=0&filter=&players=0 P.S., every 1B in MLB is negatively ranked on Fangraphs DEF overall stat. It's a positional adjustment. Gotta look at where they stand amongst other 1Bs, not all defenders. Kepler, on defense, is 3rd ranked RF in AL, and 4th in MLB. https://www.fangraphs.com/leaders.aspx?pos=rf&stats=fld&lg=all&qual=550&type=1&season=2018&month=0&season1=2018&ind=0&team=0&rost=0&age=0&filter=&players=0 Metrics kind of like both of them on D.