This morning, Patrick Saunders of the Denver Post offered an assessment of the Rockies bullpen woes. He concluded with this suggestion: "If I were general manager Jeff Bridich, I would tell owner Dick Monfort that it's past time to spend the money or make the trades necessary to fix the Rockies' chronic problem."
Let’s hope such conversations never take place. The Rockies are starting the process of rebuilding—"starting" is the operative word. Singling out the bullpen for fixing just as rebuilding is underway would not be very wise, as relief pitchers are both the most fungible and the most unpredictable of any players on an active roster. They are also the easiest players to procure via trade, as every season bad teams have good relievers that they’ll send to a contender for a low-level prospect. It’s much easier to retool a bullpen on short notice, which is why bullpens tend to be the last part of the rebuilding process, not the first.
But let’s take a look at some of the evidence Saunders harnessed to make his case. First, he pointed to the bullpen’s awful statistics. You won’t find a contrarian argument from me trying to spin away the bullpen’s ineptitude, but it’s also important not to overstate it. The Rockies’ bullpen has the worst ERA among all major league bullpens. But ERA alone doesn’t tell the whole story.
We know that Coors Field inflates ERAs. The benefit that hitters get translates to punishment for pitchers. That’s why park adjusted statistics exist. While they are not perfect, they do make an attempt to account for environment. FanGraphs has a couple park adjusted statistics: ERA- and FIP-. The former suggests that the Rockies bullpen has been about eight percent below league average in terms of earned runs allowed, which ranks sixth worst in baseball. The latter views the bullpen in terms of its fielding independent outcomes—strikeouts, walks, and home runs—and it pegs the squad as about league average. Neither of these figures are signs of optimism, but they indicate that, while bad, the Rockies relievers are not the worst in baseball. Measured by ERA-, they’ve actually been better than the Dodgers’ bullpen; measured by FIP-, and they best the Giants. The point being that pointing to ERA only should not be the basis of judgment here.
Saunders does identify other problems, but they also lead us to conclusions other than isolating the bullpen as "the chronic problem." He writes that Rockies relievers have allowed the most walks and the second most home runs. Both of those things are true! But raw numbers rarely tell us all we need to know about baseball players, especially given fluctuations of playing time. In terms of rate, Rockies relievers have walked 9.4 percent of batters, which is tied for third worst in baseball. That’s not good, to be sure, but it’s also not anomalously bad. The Rockies bullpen isn’t suffering from gopheritis, either. Their 0.92 HR/9 ranks twelfth in baseball—it’s middling. The reason they lead the league in raw number of walks allowed and are second in raw number of home runs is because they have pitched so much. They are tied with Arizona in innings pitched with 391 2/3, and they lead all of baseball with 1,732 batters faced.
Those last two ranks lead us to the real problem of the bullpen, as well as the real problem of isolating the bullpen as the problem: a bullpen’s success relies on the rotation. Relief pitchers, by definition, enter the game after the starters. That’s why their performance tends to be dichotomized into "securing" or "blowing" victory for the starter and the team. But a good starting rotation assists the bullpen, too. It has to put the bullpen in a position to succeed. That hasn’t happened this year.
In fact, if we return to the park adjusted stats cited above, we see that the rotation has been an even bigger problem for the Rockies this season. Rockies starters are second worst in baseball with a 5.20 ERA, they are third worst in ERA-, and they are second worst in FIP-. At the very least, the rotation has been equally as bad as the bullpen, and they have thrown over 60 percent of innings pitched for the team this year. Not only that, but it’s precisely the rotation that has led the bullpen to throw so many innings. A good way of going about improving the bullpen is to improve the rotation. It's at least a better strategy than investing a lot of money into free agent relievers, which is what the Rockies did when they signed Boone Logan prior to the 2014 season.
The Rockies have a lot of problems, and the bullpen is one of them. However, prioritizing the bullpen at the beginning of a rebuilding process is doing it backwards. The rotation is worse than the bullpen, and the park adjusted offense is below average both at home and on the road. Signing one among the cavalcade of relief pitcher free agents—such as David Hernandez, Tommy Hunter, or Bobby Parnell—wouldn’t cripple the team financially, but it wouldn’t solve any problems, either. Ideally, one of those types of players can be flipped to a contender for a lottery ticket. Still, emphasizing the bullpen now would be equivalent to treating the least consequential symptom of an all-encompassing problem.