More position previews: C | 1B | 2B | 3B | SS | OF

Relief pitcher is a position unlike any other.

The production is secondary to the role. A setup man could be the best, most overpowering reliever in all of baseball, but if he's not a closer -- one of the 30 relievers in line for saves -- he's not especially valuable in Fantasy.

Case in point: Andrew Miller.

That's not to say Miller is useless, but devoting one of your precious few lineup spots to a reliever who doesn't contribute in saves is limiting your team's potential.

And as you'll see here, it's entirely unnecessary.

Note: These rankings are intended to be just a first glimpse and aren't tailored for any specific format. In cases where the format would make a big difference, that difference is noted. 

Top 20 relief pitchers for 2018
Kenley Jansen Los Angeles Dodgers RP
Though he has been a top Fantasy closer since inheriting the role in 2012, Kenley Jansen somehow manages to keep getting better ... just like the team he closes for. He's reliably dominant and in an ideal situation for saves.
Craig Kimbrel Boston Red Sox RP
The line between Jansen and Craig Kimbrel is razor thin, and so I wouldn't fault anyone for preferring the latter. But Kimbrel did stumble a little in 2016 and plays for a slightly less dominant team. I'm reaching, I know.
Aroldis Chapman New York Yankees RP
Aroldis Chapman's 2017 was kind of like Kimbrel's 2016 -- uncharacteristically shaky, presumably because of some physical discomfort. He missed time early in the season with inflammation in his rotator cuff and seemed to get better as he distanced himself from that epsiode, so I'm thinking he'll be as good as new in 2018.
Corey Knebel Milwaukee Brewers RP
Though he didn't assume ninth-inning duties until mid-May of 2017, something was different for Corey Knebel from the get-go. Considered a closer in waiting from the day he was drafted, he has quickly become one of the very best, only needing to cut down the walks to catch up to Jansen and Kimbrel.
Brad Peacock Houston Astros SP
This season's token SPARP (starting pitcher as relief pitcher) is more proven as a starter than they usually are, which is why I'm ranking Brad Peacock  alongside the elite closers. He may deserve to be the No. 1 reliever in points leagues, where good starting pitchers typically outscore even the best closers. 
player headshot
Ken Giles Houston Astros RP
Ken Giles looked like he was on the verge of joining the Kimbrel class a couple years ago with the Phillies, which is why Houston gave up a king's ransom for him, and he finally began to perform up to that standard over the final 3 1/2 months of 2017. Then came the postseason, which was enough to shake manager A.J. Hinch's confidence in him and drop him a couple spots in these rankings.
Roberto Osuna Toronto Blue Jays RP
The number of saves Roberto Osuna blew in 2017 would have cost most closers the job, but as dominant as his other numbers were, you can see why the Blue Jays stuck with him. He also had some personal difficulties that may have contributed to his "struggles," but by what we can actually measure, he still looks like one of the best in the game.
Felipe Rivero Pittsburgh Pirates RP
Given that they viewed him as a prospective closer when they acquired him from the Nationals a year earlier, it's amazing the Pirates didn't transition to Felipe Rivero until July. Even with only half a season in the role, he looks like one of the safest sources for saves.
Sean Doolittle Washington Nationals RP
Sean Doolittle was one of the game's top up-and-coming closers while with the Athletics in 2014, but then a string of injuries took him out of the role.The Nationals showed he's still a natural fit, though, after acquiring him in a midseason trade.
Wade Davis Chicago Cubs RP
Wade Davis put the previous year's forearm concerns to rest in his one season with the Cubs , but the walks were something new. Now on the open market, his destination could alter his value, but it's fair to assume he'll serve as a closer somewhere.
Greg Holland Colorado Rockies RP
Greg Holland's trademark slider disappeared for a stretch in the second half, inflating his ERA, but otherwise, his return from Tommy John surgery was a total success, likely earning him a big payday this offseason. Leaving the Rockies wouldn't be the worst thing, as long as he's the unquestioned closer with his new team. 
Raisel Iglesias Cincinnati Reds RP
Raisel Iglesias ' transition from starting to closing couldn't have gone much better, though his dominance was partially concealed by the Reds' futility. They don't have to be playoff-caliber to make him a No. 1 Fantasy reliever, though, and they should take a step forward in 2018.
Edwin Diaz Seattle Mariners RP
It was a tumultuous year for Edwin Diaz , who had to be removed from the closer role twice to hammer out his mechanics. Manager Scott Servais never really lost faith in him, though, and the pure velocity combined with the swing-and-miss breaking ball suggests an elite ceiling.
Zach Britton Baltimore Orioles RP
Zach Britton is already known to have an elite ceiling, but ongoing forearm issues greatly compromised his effectiveness in 2017, and he was eventually shut down with a knee injury. He could be a steal here, but the uncertainty surrounding both his health and his effectiveness sinks his value.
player headshot
Alex Colome Tampa Bay Rays RP
A monstrous save total helped Alex Colome pass as a No. 1 Fantasy reliever in 2017, but he wasn't nearly as effective as during his breakthrough 2016, failing to strike out even a batter per inning (the minimum expectation for a late-inning reliever these days). Plus, it sounds like the Rays might slash payroll this offseason.
player headshot
Cody Allen Cleveland Indians RP
Though Cody Allen is an elite bat-misser on a first-division club whose FIP has at times compared to the Jansens and Kimbrels of the world, his save total is consistently, albeit curiously, low. I don't know if it's the way Terry Francona manages his bullpen or what, but I'm tired of always predicting Allen to finish higher than he does.
Brad Hand San Diego Padres RP
Brad Hand has proven himself to be an ace reliever over the past two years, and by sticking with the Padres at the trade deadline, the left-hander earned himself the opportunity to close. Of course, he's stuck with the Padres, who don't figure to be contenders for a long, long time. At this stage of the draft, you'll take the percentages even though the saves might be lacking.
Mark Melancon San Francisco Giants RP
Mark Melancon is of course a mainstay at this position, but he's coming off a lost 2017 -- one plagued by a forearm issue and, eventually, an elbow surgery that he says he had been putting off since 2012. He's still the intended closer in San Francisco, but even if he comes back full strength in 2018, he'll have the misfortune of pitching for the Giants .
player headshot
Arodys Vizcaino Atlanta Braves RP
Arodys Vizcaino wasn't the Braves ' intended closer in 2017 ( Jim Johnson , remember) and isn't their intended closer of the future (that would be A.J. Minter), but for now, he's getting the job done. And he fared well enough in 2017 -- in terms of both missing bats and preventing runs -- that we shouldn't assume he'll lose the job in 2018.
Hector Neris Philadelphia Phillies RP
The prospect of Hector Neris closing at the start of 2017 was much more promising than the reality turned out to be. The 28-year-old struggled with his mechanics and didn't have the same drop on his splitter. He was reliable enough to enter 2018 as the favorite for the role, but he won't get the most consistent save opportunities.