Scott Oberg's 0.0 rWAR can be viewed as generous. If we had used FanGraphs’ WAR model instead of Baseball Reference’s, Oberg's -0.9 mark would have placed him much lower on our rankings. The difference between these two figures can help us understand the various ways in which to view Oberg’s season. The distinction can mostly be attributed to home runs allowed. fWAR is FIP based while rWAR is based on runs against per nine, which means that home runs allowed will negatively affect fWAR more. Oberg’s FIP was 5.76 and his ERA 5.09.
Unsurprisingly, Oberg’s home run to fly ball ratio was 20.8 percent. Among relievers with at least 50 innings pitched, that was worst in the National League. This figure should regress back toward the league average 10 percent, although his low strikeout rate suggests that he’s more at risk for it to stay elevated than pitchers who prevent balls in play.
From the WAR view, Oberg’s season was either replacement level or below it. The thing about WAR, however, is that it is context neutral. And the thing about relievers is that their performance, more than any other player, is context dependent. They don't get a lot of playing time, and when they do it tends to be late in the game. While Oberg’s WAR figures might tell us something about how good of a pitcher he is likely to be in the future, they don’t tell us a great deal about how good he was in 2015.
For relievers, the best stat to evaluate how well a pitcher did his job is Win Probability Added. WPA measures how much a player either improves or hurts his team’s win expectancy based on each plate appearance. More credit is either given or taken away depending on the situation. Allowing a home run in a blowout won’t move the WPA needle much, but allowing a walk-off home run moves it a lot.
From this perspective, Oberg had a fine 2015. Oberg’s 0.40 WPA was by no means world beating, as there were 44 NL relievers with at least 30 innings pitched with a higher WPA. Only he, Justin Miller, and Christian Bergman posted positive WPA’s in relief for the Rockies. Oberg was a net positive in 2015 because he was more successful than not in high leverage situations.
That brings us to the third way to view Oberg’s season. There’s quite a difference between how Oberg posted his 0.40 WPA and how Miller posted his 0.53. Taking each of Oberg’s positive WPA appearances together, he compiled 4.79 WPA. His negative WPA appearances amounted to -4.39. Miller’s figures are 2.09 and -1.56. The distinction means that Oberg was put in a lot more high leverage situations than Miller. Indeed, only John Axford had more high leverage appearances for the Rockies than Oberg.
The way Oberg was used says more about Walt Weiss than Oberg, but it might be an indication that Oberg is going to remain in the team’s immediate bullpen plans for 2016. It might work. On the whole, it did work out okay in 2015, even if the positive contribution was neither substantial nor obvious.