Bullpens can be measure in plenty of different ways, but we know ERA doesn’t tell the whole story. Anyone who’s on base when a starter leaves gets charged to the starter if he scores, meaning the bullpen’s ERA gets off scott free. If you look at the Nats bullpen ERA, it’s not good, but it’s not atrocious. They’re sitting at 3.79, which you wouldn’t think would be horrible, but it ranks them 12th in the NL, so there is obvious room for improvement.
But since the ERA doesn’t tell the whole story, where else can we look? An obvious choice is inherited runners scored, which measure those guys that get home when they come in, but aren’t credited to the individual pitching. The Nats rank 13th in the NL here, at 33%. But since they’ve had more inherited runners than other teams, they actually are the worst in terns of total inherited runners scored in the league.
Couple that with this factoid – there is no team on the list worse than them in BOTH of those two categories (bullpen ERA and inherited runners scored percentage) – and you could make the case that the Nats have had the worst bullpen in the NL so far this year. I’m not quite there, though. Houston’s has been worse in ERA by a significant amount with a 32% inherited runners scored mark. A good case could also be made for Arizona. It may not be the overall #1, but the Nats are certainly among the worst right now.