Arcia—regardless of the metric used or the website that calculates it—has been elite at shortstop.
Fangraphs calculates he's saved 8 runs, first among all MLB shortstops—right above Francisco Lindor—and just behind former Brewers center fielder Carlos Gomez as the top-rated defensive player in all of baseball.
As for the rest of the team, Shaw has saved 6 runs, the highest total among MLB third basemen and ninth best in overall. Cain has saved 5 runs, fifth among center fielders and 22nd overall and Domingo Santana has saved 5 runs, sixth among right fielders and 26th overall.
The defense is a big reason the Brewers currently sit 26-18, tied for first in the NL central with the surprising Pittsburgh Pirates, especially considering their struggles with starting pitching.