His FIP is 3.89
, xFIP is also 3.89
, tRA* is 4.13
(19th best reliever), K/9 is over 11, and his BB/9 is a middling 4.
The only thing that's way out of whack is his .420 BABIP! Even higher after today's performance.
Now the Nat's defense sucks but that's ridiculous. His BABIP WILL come down and as long as he keeps up his other peripherals he should be able to put up a solid 4.0 ERA from here on out with great K numbers and a few saves and holds thrown in there. The fact is he's pitching great, he's simply getting killed by bad defense and simple bad luck.
Now there is of course the chance that he loses his closer job if the Nat's don't realize he's simply being unlucky but since they have no other good options and they see him as the closer of the future I think he will continue getting the majority of the save opps in DC.