1/3 of the way into the season, and the Nats bullpen is 6th in relief fWAR. ERA is only 12th, but FIP is 6th.
They throw hard but do not get many Ks. 22nd in K/9, but 8th in fastball velocity.
High in BABIP (21st at .295), but lots of ground balls (8th at 45.1%). Not giving up homers when balls are elevated has helped, too (6th at 8.9% HR/FB). 4th lowest FB% suppresses homers as well, and 2nd lowest LD% means there's just not a lot in the air against them. TBH, with any infield defense and the low LD rate, the batting average against (22nd at .240) should be much better.
As much as we think Davey doesn't let his starters go deep, the Nats are actually 7th from the bottom in bullpen innings, making that fWAR compilation even more impressive.
Davey is one of the more active managers when it comes to pulling his relievers mid-inning (4th in MLB). I think that comes in part from not wanting to press guys when they seem off, and in part from his willingness to bring in Harvey and Finnegan to close out innings and come back to start the next. Law and Harvey are two of the primary set up guys for the season, and they have been pulled 48 times. In fact, Law is tied with Hunter Gaddis of Cleveland for 1st in the majors in pulls at 25, and Harvey is tied for 6th at 23. Top 5 Nats in pulls have been taken out 104 times (floro and Garcia 19, weems who was in 6th/7th inning ahead duty for a while 18).