I am doing the stupidest thing possible. Not only am I writing a post about how the bullpen has been good lately — always an idea that will make you look like an absolute moron — but I am doing it before the Giants play in Coors Field. I am, simply, begging for the baseball gods to not only ruin my favorite team’s chances of winning this series, but also I’m desperately pleading for them to make me look awful.
Please. Please, sirs and madams. Please prove to my audience that I have no idea what I’m doing. Please makes all of us feel awful about our life choices after Scott Alexander gives up 6 runs in a third of an inning. Please.
Is this masochism? Is this arrogance? Is this synergy with Thursday’s podcast, in which we will do our Bullpen Trust Power Rankings, and also you should give us a 5 star review? Porque no los tres?
But the Giants bullpen did absolutely improve from April to May. They went from a 6.15 ERA (28th in baseball), -0.6 fWAR unit (27th in baseball) to one with a 2.52 ERA (2nd in baseball) and 1.4 fWAR (4th in baseball). They are still, overall, 23rd in the majors in fWAR and 20th in ERA, so a bit below average, but obviously those numbers are a huge improvement from where they were on May 1.
So what’s better? Who’s driving the improvement? Well, if I had to pick one cause, it would probably be everybody getting better.
I’m serious. Everybody either got better or isn’t on the roster anymore.
Here is a complete list of Giants relievers with an ERA under 3 in April:
Tyler Rogers
Here is a complete list of Giants relievers with an ERA over 3 in May who are currently on the active roster:
Brett Wisely
Before we get to the specific improvements made by guys who are still around, and planning on making this newsletter a jinx over the next few days, let’s talk about the personnel who aren’t on the roster right now. Sean Hjelle and Cole Waites were both unimpressive in their big league time this year, and they’re now back in Sacramento. The big one is obviously Ross Stripling, who was splitting his time between starting and relieving before he got hurt, though not very effectively in either case.
But even Stripling, when you look at his numbers, wasn’t quite as bad as he appeared. A huge part of his poor start to the year has been his astronomical rate of fly balls that turn into home runs, which is completely unsustainable over the long run. 35% of the fly balls he’s allowed have left the yard, compared to a standard league rate of 12%. That’s bad luck, and with enough time and innings, it’ll even out.
How can I be sure? Because it happened to the entire bullpen. In April, their HR/FB rate was 19.8%, the worst in baseball by more than a full percentage point. In May, it was 11%, 15th in baseball. Other than Stripling, every reliever who was on the roster on both months saw his HR/FB rate decline (Stripling hung steady at a solid 50%, though that was an especially small sample size in May, when he only pitched 3.1 innings out of the bullpen).
That’s the biggest part of why the Giants bullpen had more (read: any) success in May. In April, they underperformed their xFIP by more than 2 runs; in May, they outperformed it by about one run. In essence, the underlying numbers were always closer to a middle-of-the-road bullpen than they were to a terrible one, and now they’re closer to an okay bullpen than they are to a great one.
But that doesn’t mean that they haven’t improved in other ways. The unit as a whole struck out about half a batter more per 9 innings last month than the month before, and walked about 3/4 of a batter less. Camilo Doval had been good but shaky in April; he was outstanding in May. Taylor Rogers was a disaster in April; he was phenomenal in May. John Brebbia had a high ERA with excellent fundamental numbers in April; he had a low ERA with solid fundamentals in May.
And then there’s Sean Manaea. Manaea was signed as a starter over the offseason, and that didn’t go well, so the team moved him to the bullpen full time just before Stripling’s injury. And last month, he looked like the pitcher the team signed him to be. In 10.2 relief innings in May, Manaea pitched 10.2 innings, struck out 16, walked 3, and gave up just one run. His fastball had tons of life on it. He was able to put batters away. He went from a liability to an asset. Something similar happened with Jacob Junis, giving the team two strong options in long relief, eating up important innings every few games.
Also, Ryan Walker and Luke Jackson made their Giants debuts and couldn’t have looked better. Don’t want to overlook that!.
Will the Giants bullpen continue to have a 2.52 ERA for the rest of the year? Gosh, that’d be nice. Realistically, no; their strand rate was a little high in May and their BABIP was a little low, and some regression is due in both cases that means they’ll give up more runs. But the progress they made was real and significant. Instead of what they had in April, which was Tyler Rogers and then Doval if he wasn’t feeling overly Brian Wilsonish, the team has a full complement of strong major league relievers. If the Giants hope to have another month like May, when they went 17-12, that’s a good start.