The Nats don't have enough hitters. No more complicated than that. I don't think the Orioles have crap pitching. I suspect that the AL is stronger overall, so the pitching numbers can't be compared.
So convert his ERA to NL ERA and it's 5 instead of 6? This is what's so frightening about this upcoming series. The Rockies have nothing but bad pitchers and I fear we'll have trouble scoring against them too.