Woe to the man who tries to predict absolutely anything even remotely related to relief pitching.
It's brutal -- the most unpredictable area of a decidedly unpredictable sport. Koji Uehara got the last out of the 2013 World Series. A year ago at this time, he was probably fourth on Boston's bullpen depth chart.
So as we continue this top-10 series -- having already tackled the rotations, lineups and defenses -- take all of the below with a sizable grain of salt. Bullpens are subject to change, and so, inherently, are rankings of bullpens. It is a virtual lock that some team not mentioned below will wind up in the top five, in terms of effectiveness, in 2014.
For now, here are the teams that appear to have the best bullpens heading into Spring Training camp.
10. RED SOX
This was an erratic unit for much of 2013, but it's hard to argue with the way Uehara pitched, especially down the stretch: a 0.28 ERA and .231 OPS against and 0.313 WHIP (!) in the second half. Crazy numbers, though the problem of overwork is possible, considering he made 86 appearances, counting the postseason. Boston can counter that with some interesting options such as the newly signed Ed Mujica, who was a dominant closer for the Cards before falling off late last season, and Andrew Miller, who had a 14.1 strikeouts-per-nine-innings mark before breaking his left foot last summer. A weakness at times in 2013, the bullpen should be a source of strength for the Red Sox in '14.
The A's had the sixth-best relief ERA in baseball last season, but some of the advanced metrics rated them more toward the middle of the pack.
Perhaps it's no surprise, then, that general manager Billy Beane did some tinkering this winter. Jim Johnson, acquired from Baltimore, is a good, albeit costly, get. He doesn't have swing-and-miss stuff, but he gets ground balls and should fare well at O.co Coliseum. And Beane swapped outfielder Seth Smith to the Padres for right-hander Luke Gregerson, who should be an effective setup man after posting a 1.010 WHIP last year. He'll partner with Ryan Cook, who averaged exactly one strikeout per inning last season and is stingy with home runs, and highly effective lefty Sean Doolittle.
Why do I get the feeling Heath Bell will be the latest to be cured by the waters of Tampa Bay? The Rays routinely turn in successful bullpens, and 2014 should be no different, especially if Bell reclaims even a smidgen of what once made him a lockdown closer for the Padres. Juan Carlos Oviedo is another interesting reclamation project, and he and Bell could pair with Joel Peralta and Jake McGee to create a strong setup tandem.
More important, landing free agent Grant Balfour after his failed physical with the Orioles should give manager Joe Maddon some needed clarity about the ninth inning. Balfour has a 1.052 ERA over the past four seasons (and do you think he'll be amped up when he faces Baltimore?).
7. BLUE JAYS
The bullpen was a bright spot -- and a surprising one, at that -- in an otherwise roughshod 2013. There was no telling if Casey Janssen and Dustin McGowan, in particular, would stay healthy enough to contribute, but they both posted ERAs below 3.00. Janssen blew just two saves in 36 chances and had a 0.987 WHIP. Sergio Santos returned from arm trouble to post a 1.75 ERA and 0.584 WHIP in 29 appearances. Left-handers Aaron Loup (2.47 ERA in 64 appearances) and Brett Cecil (2.82 ERA in 60 games) were both effective. Unfortunately for Toronto, all of it was in support of an awful starting staff that pitched the third-fewest innings in the Major Leagues.
Only the Twins, Rockies and Blue Jays, all of whom had terrible rotations, asked for more innings out of their relievers than the Pirates did last season. But context counts: Skipper Clint Hurdle was quite careful with pitch counts and he limited the number of no-rest outings.
So the "Shark Tank" survived the weight of the season, even when out-of-nowhere All-Star closer Jason Grilli missed six weeks with an arm injury. In Grilli, Mark Melancon, Tony Watson, Justin Wilson and Vin Mazzaro, the Pirates bring back all the principals, and Hurdle's astute game management could continue to get the best out of them.
With so many rotation candidates in play, it's uncertain whether Carlos Martinez, with his awe-inspiring stuff, will be a reliever or starter. Whatever the case, Trevor Rosenthal is staying put at closer for a Cards club that keeps reinventing its bullpen on the fly and keeps coming up with effective solutions.
Think about how dazzling the Martinez-Rosenthal combo looked in Game 2 of the World Series and it's easy to get swept up in the thought of what a weapon they'd be in a full season, especially when flanked by left-handers Kevin Siegrist (0.882 WHIP) and Randy Choate (1.047) and right-hander Seth Maness (2.32 ERA). The Cards could also benefit from the return of former closer Jason Motte. There are arms aplenty here.
The Reds will stick with Aroldis Chapman in the closer's role, and at this point, it's hard to blame them. Even if Chapman didn't reach the downright historic level he ascended to in 2012, he nonetheless struck out 15.8 batters per nine while allowing only a 1.037 WHIP last year.
And with right-handers Alfredo Simon, J.J. Hoover and Sam LeCure (all of whom had adjusted ERAs at least 33-percent better than league average) and left-hander Manny Parra in the mix, to say nothing of returns to health by veterans Jonathan Broxton and Sean Marshall, the Reds should again have a bullpen that rates as a team strength.
Any bullpen with a $10 million setup man -- Brian Wilson -- had better be good. Wilson made a triumphant return from his second Tommy John elbow surgery last summer, and he makes for an excellent bridge to Kenley Jansen, who struck out 111 and walked just 18 in 76 2/3 innings pitched last season.
The Dodgers re-signed lefty J.P. Howell (1.048 WHIP, 2.03 ERA) and added ground-ball machine Jamey Wright (3.00 ERA), who is coming off a career year with the Rays. The real intrigue in the Dodgers bullpen will be what they get out of two former All-Star closers -- Brandon League and Chris Perez. All in all, there is strength in numbers for a staff that had to lean heavily on Jansen, Ronald Belisario and Paco Rodriguez last year.
An improved innings total by the starters allowed a Royals bullpen that already was pretty strong to take the leap into the elite. This is where the Royals' 2013 bullpen ranked since the advent of the designated hitter in 1973: 2.55 ERA (second-lowest), 1.133 WHIP (sixth-lowest), 9.57 strikeouts-per-nine (second-highest), 3.07 strikeout-to-walk ratio (fourth-best), .217 batting average against (sixth-lowest).
Greg Holland is the game's best closer not named Craig Kimbrel, and Luke Hochevar reinvented his career as a reliever. They made the Royals the first team ever to have two relievers with at least 60 innings pitched, a strikeout rate of 10.0 or better and a WHIP below 0.90. With Aaron Crow and Tim Collins due for bounceback years and Kelvin Herrera, Louis Coleman and Donnie Joseph in the mix, the Royals have a good chance of continuing their relief success into this season.
The Braves had the best bullpen ERA in the Majors -- again -- and they did it despite losing key cogs Jonny Venters and Eric O'Flaherty to surgery in May. In an area of the game prone to tremendous fluctuations, Atlanta has the lowest relief ERA in the big leagues over the past seven seasons. That's no small sample.
Obviously, so much of the Braves' bullpen success the past few years has revolved around Kimbrel, who has amassed 381 strikeouts while allowing just 123 hits in 227 1/3 career innings. He has a ridiculous 0.902 career WHIP, and best of all, he's not quite 26 yet. He is a supreme talent at the peak of his powers. A great closer needs a supporting cast, though, and Kimbrel has an excellent one in David Carpenter, Jordan Walden, Anthony Varvaro and left-hander Luis Avilan, and it's possible that Venters returns in midseason after his second Tommy John surgery.
Honorable mention: If Neftali Feliz returns to something resembling his 2010-11 performance, the Rangers will rise up these rankings, and there have been encouraging reports about him in winter ball. … The Padres should be in good shape with Joaquin Benoit setting up Huston Street, and lefty Alex Torres is an intriguing addition. … Signing the incredibly consistent Joe Nathan was a necessary step for a Tigers team that had a terrible bullpen much of last season, but the jury is still out on Bruce Rondon and Al Alburquerque and the newly acquired Ian Krol and Joba Chamberlain. … The trade for Addison Reed should augment what was a middle-of-the-pack D-backs bullpen in 2013. … Former key cogs John Axford and Francisco Rodriguez were traded away last season, but the Brewers posted the fifth-best relief ERA in the game -- after ranking dead last in 2012 -- thanks to the emergence of Jim Henderson and Brandon Kintzler, who proved to be an effective closer-setup tandem. … The Giants ranked eighth in ERA, but Sergio Romo, Santiago Casilla and Jeremy Affeldt all had control issues.
Anthony Castrovince is a reporter for MLB.com. Read his columns and follow him on Twitter at @Castrovince.