Let’s hope it goes better than last night, shall we?
Last night, Shelby Miller turned in a performance worth -80.2% of win probability. It wasn’t quite the worst of the year for Arizona – Miller himself rated -80.9% in an extra-inning loss to the Dodgers on May 20. But it did drop the Diamondbacks’ bullpen as a collective entity into dead-last place in the majors this year, for Win Probability by relievers. All told, they have been worth -291%. Only three other teams – the Athletics, White Sox and Nationals – are even below zero in this metric. [This is normal: by the nature of the metric, pitching typically is well above zero, while hitting is well below it, because an out – success for a pitcher, failure for a hitter – is the most likely outcome]
If you break it down to the individual level, you can see who is responsible. Despite Miller being responsible for the two biggest meltdowns of the season, his overall number is not terrible: -45%. Closers will, inevitably, tend to end up with the biggest impact, since they usually pitch in situations with the potential to go to 0% or 100% of WP. That’s not the case for middle relievers. You can see this at the top of the chart, where our two best relievers are A.J. Puk and Justin Martinez: sadly, there’s a significant chance we will not see either of them take the mound again this year. Outside of them, Jalen Beeks has been the best bullpen arm by WP.
Fangraphs also used meltdowns and shutdowns: these are appearances which shift the WP by more than 6% in the appropriate direction. It’s interesting to note that Beeks and Miller have the same number of meltdowns (4), and Miller actually has four MORE shutdowns (14 vs. 10). But Miller has a total WP 84% worse than Beeks. I suspect that’s because of the situation noted above: when Miller fails, it’s a lot worse than Beeks failing. Here are the worst outings this year by D-backs. Miller’s two worst total -161%; Beeks’ two worst are only –93%. But overall, those other teams with sub-zero bullpens are basically awful. The Nats have the best record among them, and they’re still 30-43. It’s bad company to keep.