Analysis here gets a little more vague and "finger in the air," because things like WAR don't have as much relevance to bullpen arms as in other positions. Projected ERA seemed about the closest metric. So, let's see who's going to have most confidence in the ninth, and who'll be reaching for the Maalox?
#1. Dodgers: Kenley Jansen (Projected ERA: 2.11)
Right out of the gate, we have a caveat, with Jansen missing the start of the season after having surgery to remove a growth from a bone in his foot. He'll be out 8-12 weeks, the mid-point of which would be about the end of April. That's going to hurt Los Angeles, with no obvious alternates. Joel Peralta? Brandon League? Pedro Baez? Anyone will be a long drop from Jansen, who put up a 2.76 ERA last year, despite being BABIP'd around at a .350 clip. Over the past three years, more than half his outs have come by the K, which puts him among elite company. In terms of the NL, Aroldis Chapman and Craig Kimbrel are likely better, but Jansen can't come back soon enough for LA.
#2. Padres: Joaquin Benoit (2.66)
Amusing bit of trivia: up until they signed James Shields, Benoit was the possessor of the most-expensive contract ever given by San Diego to a free-agent player, at the princely sum of $15.5 million. Though his year was slightly curtailed (he had only three appearances after August 26), he certainly lived up to it in 2014, his 1.49 ERA the second-best in the National League (behind the Nationals' Drew Storen at 1.12) of any pitcher with fifty innings of work. He took over as closer from Huston Street after the incumbent was dealt to Anaheim, but could end up following the same road out of town if San Diego don't compete, given his impending free-agent status.
#3. Diamondbacks: Addison Reed (3.31)
Really, the rest of the division, you could pull the names out of a hat and I wouldn't argue with the resulting order. But I'd be pretty satisfied with the projected 65 innings at a 3.31 ERA. Is that plausible? In 2014, Reed's strikeout rate was the highest since becoming a full-time major-leaguer, and the walk rate his lowest. What really hurt him was the long ball, with 11 allowed in 59.1 innings - almost a quarter of all home-runs allowed by our bullpen (47). As we discussed at the All-Star break, if his HR/FB returns to his career average, or even MLB average, that will be a huge help, since 17 of the 31 runs Reed allowed in 2014, came as a result of those blasts.
#4. Giants: Santiago Casilla (3.43)
You may wonder why Casilla's projected numbers are so high, because over the past five years, he has been super-consistent: 50+ innings and a sub-three ERA every time. Clayton Kershaw is the sole other pitcher with that. Kimbrel, At a 2.10 ERA since the start of 2010. Eric O'Flaherty and Koji Uehara are the only pitchers with 200 IP and a better ERA. The problem is, his FIP over that time has been a lot higher, up at 3.47, and I think that's where the prediction comes from. He also fanned only 6.9 batters per nine IP in 2014; league average for relievers was 8.6. That's a fair few of balls in play. Turns 35 in July, but his velocity remained solid last season.
#5. Rockies: LaTroy Hawkins (4.03)
As he goes into his 21st major-league season, you have to respect the venerable Hawkins, one of only three active pitchers who debuted before the D-backs came into existence - born in 1972, he was the oldest pitcher in the majors last season, yet still put up a 3.31 ERA in Coors Field [that's an ERA+ of 129]. Age certainly hasn't slowed him down: over the past four years, he has an ERA+ of 128, averaging 57 appearances. But he's had enough, and he has said this will be his final year, as he wants to spend more time with his family. He has exactly 1,000 major-league appearances, and will likely end his career in the top ten all-time there, with an outside shot at the top five.
We've said it before. Relievers are volatile,and the concept of the "proven closer" is close to a mirage. So it wouldn't surprise me if multiple teams in the division end 2015 with different closers from Opening Day, whether through injury or ineffectiveness. The Diamondbacks are in a bit better shape there than some, as we do appear to have a number of credible candidates if Reed needs to be replaced, or simply a day off: Brad Ziegler and Evan Marshall are perhaps the front-runners. But I'd rather Reed did the job and did it well. He's #9 in the majors for saves over the past three seasons, but his ERA+ in that time is only 97, so it's more a factor of opportunity than effectiveness.