The Arizona Diamondbacks bullpen was historically bad in 2010. In 439 innings, they allowed 307 runs to score, 280 of which were earned. That comes out to a 5.74 ERA, over a full run more than the next worst team (the Cubs, 4.72). On top of that, the Diamondbacks also allowed 78 of 189 inherited runners to score, a 41% mark which ties the Dodgers for the worst in the Majors. It shouldn’t be surprising, then, that the Diamondbacks’ -8.37 WPA is nearly three wins lower than second worst and the worst WPA for any team since the 1999 Kansas City Royals, a team which featured such stalwarts as Tim Byrdak, Scott Service, and Jeff Montgomery.
The pure, unadulterated incompetence of this past year’s Diamondbacks team has allowed another bullpen to go under the radar. The Seattle Mariners bullpen put up a paltry -5.51 WPA, a number that would typically be in a dogfight for worst in the league. Mariner relievers were also the only other team unit to go below replacement level in 2010, with the run suppressing effects of Safeco Field masking just how poor they pitched, keeping their ERA at a merely mediocre 4.23.
What is most remarkable about Seattle’s bullpen struggles is how it required a vastly superior clutch performance to reach a WPA mark that typifies the worst bullpen teams in the league. The Mariners ranked fourth in clutch, as measured here by WPA/pLI – WPA/LI, only behind the Rays, Cubs, and Royals. Without that clutch factor, the Mariners posted an unbelievably horrible -9.13 WPA/LI over four wins worse than the Diamondbacks and worse than any team in the millennium, and even worse than those aforementioned 1999 Royals.
Mostly thanks to the total ineptitude of the Mariners’ offense, Seattle relievers entered the least high-leverage situations in the American League, at 134. They also have by far the least relief appearances in the Majors. Due to the fact that, by and large, these relievers were entering in unimportant situations, the Mariners weren’t quick with their hooks at all. Seattle saw the fewest outings of fewer than three outs in the whole league and were near the bottom in percentage of appearances lasting less than a full inning (20% vs. 29% average). It appears that the willingness of the Mariners to leave their relievers in once they entered – particularly in low-leverage situations – was a major factor for why their leverage-neutral results appear so much worse than their actual results.
Take Chris Seddon, for instance. He appeared in 14 games (22.1 IP) and pitched like a minor leaguer, with a 5.64 ERA and a 5.32 FIP. Despite allowing tons of runs, Seddon recorded one of the few above-average WPAs on the team, at +0.11, which is because most of the beating that Seddon took – 1 IP, 2 ER against CLE, .2 IP, 3 ER against NYY, and 1 IP, 3 ER against TB – all came with pLIs below 0.14 and even with one as low as 0.00. Those appearances account for 57% of Seddon’s earned runs but only added up to -.032 WPA . In his only four games facing a pLI above 0.5, Seddon faced 20 hitters and only two of them reached base as he compiled a +.199 WPA in those situations.
It’s hard to blame Seattle for having long leashes as they trotted out multiple awful bullpen arms over the course of a long season. In high leverage situations, they could turn to David Aardsma and Brandon League – two talented pitchers who had at least respectable seasons in 2010. In low leverage situations, though, the Mariners were scraping the bottom of the barrel. The Mariners weren’t as historically bad as the Diamondbacks, partially because they didn’t give up as many runs and partly because they picked their spots better. But just looking at the performance of the bullpen as a whole, without regard for leverage, the 2010 Mariners were easily the worst bullpen of recent memory and possibly the worst in history.