Attrition is Catching Up to Oakland’s Bullpen and Playoff Odds

The A’s are nearly on the outside looking in. With about two weeks left in the season, there’s still room for a pair of AL East cold streaks to swing things around, but the odds of Oakland reclaiming a Wild Card spot and making the playoffs for a fourth straight year are slim.

Those odds cratered in the past month; some of that collapse is more succinctly summarized here. Any four-year playoff run is impressive, but the Oakland teams of the past three years, including two 97-win squads, have been devoid of the quality of starting pitching that their record would suggest. This season will be the first the A’s have had in that stretch with any starting pitcher compiling 3-plus WAR, let alone three of them. But while the gains in starting pitching are most certainly helpful, there has been a considerable dip in the quality of Oakland’s relievers.

The Athletics’ bullpen this season has not been horrible. They sit in the bottom half of the league by WAR but have held a league average ERA up to this point. But over the past month, they’ve had the third worst WPA in the league (-2.97), as well as a 5.85 ERA. About a month ago, I wrote that this was going to be the first year in Oakland’s run that a reliever didn’t lead the pitching staff in WAR. Blake Treinen and Liam Hendriks put up some of the best reliever seasons of this century, so maybe there’s something unfair about that comparison, but they were necessary anchors to highly successful teams, posting a combined 11.05 WPA from 2018 to ’20. 

The Athletics’ front office still has to operate with ownership personally squeezing every penny with a vise, which means that a good thing can’t last for long. Hendriks and Treinen were never going to be kept around, and there was no easy way to replace their level of production. A one-year, $11 million deal with Trevor Rosenthal was supposed to be a band-aid for Hendriks’ lost production — until Rosenthal was lost for the year in July. That wasn’t just about the money blown, though; it’s strikeouts — which Rosenthal was supposed to provide in spades — the bullpen has been missing desperately.

A’s Bullpen K-BB%
Season K-BB% (whole pen) K-BB% (no Hendriks/Treinen)
2018 14.8% 13.4%
2019 15.7% 13.9%
2020 17% 14.6%
2021 11.9%

Bullpen usage is far beyond strikeouts, though; it’s much more about preserving your win probability. That’s been just as big a problem for the A’s this season:

A’s Bullpen WPA/LI
Season WPA/LI
2018 6.3
2019 5.32
2020 3.56
2021 0.72

Oakland went from top five in the league over the last three seasons to middle of the pack.

Life beyond Hendriks or Treinen has been the reality for quite some time now, though, and neither was single-handedly carrying the bullpen. But outside of those two, there has been only one regular relief presence for the A’s in that span: Yusmeiro Petit and his 3.01 ERA over 269 innings. And now even he is beginning to crack.

Yusmeiro Petit’s Time in Oakland
Season IP FAv K% ERA
2018 93.0 89.5 20.7% 3.00
2019 83.0 89.3 23.1% 2.71
2020 21.2 88.3 19.3% 1.66
2021 71.1 87.8 12.2% 3.79

In many ways, Petit is the embodiment of many of the non-Hendriks/Treinen A’s relievers of the past few years: he’s older, doesn’t throw particularly hard, doesn’t strike out a lot of people, and came cheaply. At 36, he isn’t the resident graybeard in the bullpen this year (Sergio Romo is 38 years young), but the A’s have had the oldest relief corps in the league every year since 2018, with an average of 30.7 years old. Fernando Rodney, Santiago Casilla, Joakim Soria, Romo, and Petit have all thrown 30-plus innings in that time as free-agent signings in their age-35 or above season. This is what the team has leaned on outside of Hendriks and Treinen: build around a bullpen ace with cheap, contact-quality arms, playing to the benefits of the home run suppression of the Oakland Coliseum. 

Maybe this was all inevitable once Rosenthal was lost for the year, and maybe Andrew Chafin arrived a little too late. While this Oakland team is by no means bad, it’s becoming clear that the attrition brought on by payroll or whatever you want to blame is taking its toll and leaving too many holes in the roster that can’t be papered over. This is the first year in awhile without a bullpen stud for the A’s, and that might be what ends the playoff run and kickstarts another rebuild.

Owen is a contributor at FanGraphs. He got his start blogging about baseball when he was in college and you can find him maybe talking about something on Twitter @O_dotco.

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2 years ago

It’s also self inflicted. A’s have bullpen arms in the minors with extremely gaudy strike out ratess/ numbers. But instead of cutting off the chaff and being aggressive in promoting those guys they remained overly conservative.

They left the best reliever in AAA West down all year in favor of holding onto players like Reymin Guduan and Burch Smith. And nobody stepped in to stop Melvin from overusing Petit again, (third in IP as a 36 year old with the lowest k rate in baseball)