The Unlikely Ascent of Oakland’s Bullpen

There are a lot of things going right in Oakland these days. For one thing, there are early indications that a red-hot rental and home-ownership market might finally be cooling off, even if only slightly (and very tentatively), thereby bringing four walls and a roof somewhat closer to reach for hundreds of thousands of ordinary Americans in the Bay Area. For another, the unemployment rate continues to drop (although wage growth is persistently and irritatingly slow to rise). And for a third, the Oakland Athletics have been the best team in baseball (west of Jersey Street) for over a month.

For a team to go 22-8 over any stretch, as the A’s have just done since July 10th, when they were last 10 games back of the Astros, requires a lot of things to go right. It requires Tony Sipp to hang a slider to Matt Olson. It requires a sweep of Texas on the road. It requires, in short, a little bit of that fairy dust that seems to have been scattered around the HoHo Coliseum since the days when Scott Hatteberg and Jonah Hill wandered those green fields — and the A’s have had that and all these things. But it also requires a lights-out bullpen, which the A’s have manifestly also had in recent days, and it’s this feature of the club’s recent experience on which I’d like to focus for a moment, because it wasn’t clear at the beginning of the season that this level of bullpen success was something the A’s would achieve or even necessarily aspire to.

The 2017 edition of the Oakland bullpen mostly sucked. By FIP (4.44), it was the ninth-worst in the game, by ERA (4.57) the sixth-worst, and by WPA, which is as close a measure as you can get to answering the question “was this bullpen good when it counted?” it was rock-bottom — the very worst in the game. If all you knew about the 2018 edition of the A’s pen is that it would no longer include Ryan Madson (who recorded a 2.06 ERA last year), you might project that it would take a step backwards this year, even after accounting for the winter additions of xwOBA darlings Ryan Buchter, Chris Hatcher, and Yusmeiro Petit in a busy offseason for Billy Beane.

But it turns out those three additions — and their shared ability to limit hard-hit balls in the air — were at least part of what this bullpen needed to break out, despite Hatcher’s middling performance. Throw a significantly reduced role for Liam Hendriks (whose velocity is down across the board this year, quite possibly due to overuse last year) and breakout seasons from holdover Blake Treinen (who leads the majors in relief ERA by quite a margin) and rookie Lou Trivino, and you’ve got yourself a recipe for one of the better bullpens in the game to date. As a group, they’ve recorded the game’s sixth-best park-adjusted ERA, and although some higher-order statistics (FIP, SIERA, etc.) don’t look quite as good for this crew, the results have been there since day one.

As Jeff Sullivan noted in the piece linked above (and again here), the A’s bullpen success this year — particularly as it’s been driven, to a large extent, by its top two performers in Treinen and Trivino, and because the team is consistently outperforming its peripherals — is one of those things that’s easy to point to and say, well, that won’t last. But it’s been a month or so since Jeff wrote that piece, and Treinen and Trivino’s combined ERA- was 26. It’s 30 now. However inevitable regression might be, that doesn’t negate what the bullpen has done for over three-quarters of a major-league season. And whatever the value of the advanced metrics to better understanding the future, what the club ultimately cares about is results.

There are actually signs that the 2017 edition of the A’s bullpen wasn’t as bad as it seemed — you’ll note that that crew underperformed their FIP by a few tenths of a run, just as this year’s crew is overperforming their FIP — and so maybe some part of the A’s apparent breakout is that they were better than they seemed last year and aren’t quite as good as they appear this year. There’s also the A’s defense, which improved. Still, the A’s relievers are pretty much to a man better this season than they were last (Hendriks being the notable exception), and the new additions are almost all better than the people they replaced (with Madson the exception here).

And there’s also the small matter that the non-Treinen, non-Trivino A’s have gotten better, not worse, in recent months, and have performed closer to their peripherals with every passing days. Since July 10th — which is when their current run of success began — Jeurys Familia has thrown 13 innings for a .230 wOBA. Emilio Pagan has thrown 11.2 for a .230, and Petit 20.1 for a .256.  As a group, the A’s relievers’ .264 wOBA since July 11th is by 10 points the best in the game (ahead of Dave Cameron’s Padres), and their 2.77 ERA is the only one in the league below three. In the beginning of the season, the A’s pen was seeing modest success without the peripheral results to back it up. In the last month or so, their on-field success has improved dramatically at the same time as their peripherals have caught up to that performances.

If the A’s are going to catch the Astros in the AL West this year — which would clearly represent a shock given the preseason expectations for both teams — a lot of things are going to have to keep going right. The Matts, Chapman and Olson, will have to continue their run success. The bottom part of the lineup will have to continue to be surprisingly good. The starting pitching will have to keep doing whatever it is they’re doing (or improve — there’s definitely still room to do so). And the A’s bullpen, which was among the league’s laggards last year, will have to continue doing what it’s been doing for the whole of 2018 and especially for the last month: limiting the damage and stopping the bleeding.