With Spring Training on the horizon, MLB.com columnist Anthony Castrovince is compiling his annual series of Top 10s. We began with the lineups and rotations, continue now with bullpens and will have an overall power rankings on Thursday before discussing defenses on Friday.

A good bullpen has long been considered an important ingredient in the big league recipe for success. But never in the history of the game have bullpens, by and large, been this stacked with hard-throwers. And never has the mid-inning matchup game been this consequential. There are a lot of reasons for the league-wide decline in offense, but beefed-up bullpens are often cited -- by managers, players, evaluators -- as the biggest.

While acknowledging that bullpens are inherently fungible, volatile areas and that all of the information below is subject to change, these are the 10 clubs best-situated in the bullpen department as camps open in Florida and Arizona:

10. Nationals

I'd have them much higher had they kept Tyler Clippard, though one can certainly understand parting with that price tag (and hey, maybe the Nats know something about him that we don't). The Nats have signed Casey Janssen to a one-year deal with just $5 million guaranteed -- a lottery ticket that could provide a big payoff if Janssen can shake off his second-half regression (following a bout with food poisoning) in 2014 and get back to something more closely resembling his '13 stat line -- a 2.56 ERA, 23.8 strikeout percentage, 47.9 ground-ball percentage and 0.51 homers per nine innings.

Even if Janssen doesn't pan out, the setup situation in front of Drew Storen (who, of course, has yet to prove himself on the October stage) is hopeful. Aaron Barrett had a 2.59 FIP and 49 strikeouts in 40 2/3 innings, and veteran lefties Jerry Blevins and Matt Thornton both had FIP marks of 2.77 or below with the Nats last year.

9. A's

The Sean Doolittle situation obviously merits monitoring, which is why the A's aren't higher here. Doolittle has a slight rotator cuff tear and is rehabbing after receiving a platelet-rich plasma injection. He's doubtful for Opening Day.

But the depth here is undeniable, with Clippard (2.18 ERA, 0.99 WHIP) acquired to replace departed free agent Luke Gregerson, and Ryan Cook (3.42, 1.08), Dan Otero (2.28, 1.10) and lefties Fernando Abad (1.57, 0.85) and Eric O'Flaherty (2.25, 0.95) all aboard. The A's had the second-lowest relief ERA in the AL last season. We'll see how long the Doolittle situation lingers as they try to build on that precedent.

8. Marlins

In terms of WAR, Miami's relief staff ranked sixth in all of baseball last season, which is one reason why this club was more competitive than many had imagined going into the year.

There are not a lot of household names here, but underrated closer Steve Cishek (2.35 FIP, 1.141 WHIP and 73 saves over the last two seasons) gets crazy good results against batters on both sides of the plate despite a crazy arm angle that you would think would leave him susceptible to lefties (lefties actually hit him significantly worse than righties last year). Midseason trade acquisition Bryan Morris posted a 0.66 ERA in 40 2/3 innings for the Marlins, and he joins A.J. Ramos (2.11 ERA) as a strong setup option. Mike Dunn (67 strikeouts in 57 innings) is solid from the left-hand side. Trade acquisition Aaron Crow could be a bounce-back candidate in the National League.

On the "household name" front, the Marlins have kicked the tires on free-agent Francisco Rodriguez in recent weeks. But this unit looks sturdy even without any other additions.

7. Cubs

Before Jon Lester, before Joe Maddon, before Miguel Montero, the one area of their club that Cubs officials could point to and feel really good about at the end of the 2014 regular season was the bullpen. It made major strides as 2014 evolved, with closer Hector Rondon (9.0) and setup men Pedro Strop (10.5), Neil Ramirez (10.9) and Justin Grimm (9.1) all striking out nine batters per nine or more. Rondon, Strop and Ramirez combined to give up a grand total of six homers in 168 innings, and they all had FIP marks of 2.66 or lower.

Throw in a worthwhile flyer on one-time World Series closer Jason Motte, and you've got a strong outlook for the Cubs as they try to rise up the NL Central standings this season.

6. Giants

Given the aforementioned instability of bullpens, in general, it's pretty amazing that so many key cogs from San Francisco's 2010 'pen -- Santiago Casilla, Jeremy Affeldt, Sergio Romo and Javier Lopez -- are still here. And those guys have, of course, been big contributors in the runs to three titles in five years.

Ask those guys how such consistency exists, and they'll point you to Bruce Bochy, who has earned a reputation for manipulating his 'pen pieces with mastery. And the re-signing of Ryan Vogelsong and Jake Peavy makes it possible for Bochy to continue to use Yusmeiro Petit as a swingman or -- maybe, eventually -- shift Tim Lincecum to relief work.

In the meantime, the Giants' main objective is to straighten out hard-throwing right-hander Hunter Strickland (a mess in October), who can take this bullpen to yet another level.

5. Pirates

When you return three guys -- Mark Melancon (1.90 ERA, 0.87 WHIP), Tony Watson (1.63, 1.02) and Jared Hughes (1.96, 1.09) -- who had sub-2.00 ERAs last season, you're off to a good start (or finish, as it were). The Pirates will also have John Holdzkom for a full season after he ascended to and astounded on the big league stage down the stretch, striking out 14 batters in his nine innings of work.

The Buccos will need new acquisition Antonio Bastardo to pair with Watson as a reliable left-handed presence.

4. Orioles

Losing Andrew Miller doesn't help, but the O's had a pretty good bullpen before they acquired the big lefty, and they should still have a pretty good bullpen without him, too.

Zach Britton's quick adaptation to the closer role (1.65 ERA, 37 saves, 0.90 WHIP) after his starting career went wayward was a sight to behold as 2014 evolved. He's set up by Darren O'Day (1.70 ERA, 0.89 WHIP) and Tommy Hunter (2.97 ERA, 1.10 WHIP). The O's also have Brian Matusz, who had a 1.42 ERA in the second half, and Brad Brach, who had a breakout year.

With Buck Showalter manning the switches and finding the appropriate roles for his available arms, you have to like the O's chances of ranking in the upper-tier in relief ERA again this season.

3. Mariners

You could just as easily put them in the top slot of this list. I'd have no complaint. Through no fault of its own, the M's 'pen didn't have the opportunity to assert itself on the October stage like the team that ranks first here, but it made its mark, all the same.

Not only did Mariners relievers post the best ERA (2.60) and fourth-best WHIP (1.16) of any big league bullpen in 2014, but they also had the ninth best strand rate (80.7 percent) in the live-ball era. It wasn't just Fernando Rodney and his 48 saves and bow-and-arrow routine. It was also Tom Wilhelmsen holding opponents to a .542 OPS against, Danny Farquhar striking out 10.3 batters per nine, Dominic Leone posting a 2.17 ERA, etc. There are hard throwers and closing or setup candidates abound in this bullpen. So even if it doesn't match '14's level, it should still be a strength of this AL West contender.

2. Yankees

Here, too, is another strong candidate for the No. 1 spot. It might seem like this was a conservative winter for the Yankees -- at least, by Yankees standards -- but there's nothing conservative about a four-year, $36 million commitment to a guy with one career save. The Yanks appreciate the value of Andrew Miller as a high-leverage asset no matter the specific role. He was a difference-maker in the AL Division Series for the Orioles last October, and he'll pair nicely with Dellin Betances in the late innings after Betances' robust rookie year (1.40 ERA, 0.78 WHIP in 90 innings).

So the departure of David Robertson might not make a big difference in the Bronx, especially if lefty acquisition Justin Wilson can approximate his 2013 numbers (2.08 ERA in 73 2/3 innings) and high-velocity right-handers Adam Warren and David Carpenter can help bridge the gap.

1. Royals

There were calls for the Royals to deal from this position of strength (and great expense, relative to the rest of the payroll) to augment other parts of their roster. And for all we know, maybe those calls had credence. But the Royals not only kept their dominant trio of Greg Holland, Wade Davis and Kelvin Herrera together, but they added to it by making the two-year, $10 million commitment it took to bring back Luke Hochevar after Tommy John surgery, so they deserve this top spot.

With a 1.92 ERA and 0.82 WHIP in 70 1/3 innings in 2013, Hochevar set a precedent, of sorts, for the dominant -- historic, even -- setup season the former starter Davis turned in last year. Davis had a 1.00 ERA, 0.85 WHIP and, incredibly, just five extra-base hits (including zero homers) logged against him. Over the last three seasons, Holland has established himself as one of the most consistent ninth-inning arms in a job not known for consistency, and Herrera compiled a 1.41 ERA in 70 innings last year.

The re-signing of Jason Frasor should help keep the Royals sturdy in the middle innings before the back end takes over.

Honorable mention: Honestly, I can count on one hand the number of teams I didn't strongly consider for this list, because even the worst 'pens from '14 could have a quick turnaround in this environment (the White Sox, Dodgers, Astros and Reds are among those who have been proactive in this area). But for now, the rest of my top 15 would be: 11. Indians (underrated closer Cody Allen has an 11.0 strikeouts-per-nine mark for his career, and Terry Francona is always proactive with his reliever usage), 12. Padres (they have a tradition of strong bullpens, and this one is situated nicely with Joaquin Benoit, Brandon Maurer and Shawn Kelley), 13. Rays (here, too, is another organization with a tradition for strong relief work, and they've added Kevin Jepsen), 14. Angels (a bullpen almost totally rebuilt on the fly last season has become a team strength), 15. Phillies (hey, they still have Jonathan Papelbon, for now, and his pairing with Ken Giles and Justin De Fratus gives possibly one of the worst teams in baseball the ironic luxury of a strong setup to seal late leads).


Anthony Castrovince is a Sports on Earth contributor and MLB.com columnist. Follow him on Twitter @Castrovince.