Holy cow, so I just took a look at the Royals' zone ratings so far on FanGraphs, and as a team they have a 30 UZR and 11.8 UZR/150, which are both first in the majors. By comparison, last season the Braves led the majors with a 10.3 UZR/150. That means the Royals defense is getting to a lot of balls that other teams' defenses wouldn't get to and making plays a lot of other teams' defenses wouldn't (which makes up for a few more errors--you're committing more errors because you're actually getting to more balls). Which certainly helps explain the low runs allowed and the low BABIP given the low K rate.