With roles becoming more fluid and fewer teams relying on a set closer, building a strong fantasy bullpen is tougher than ever.

In 2015, 21 players recorded at least 30 saves. That number dropped to 16 the next season, then 11 in 2017, ’18 and ’19. During the pandemic-shortened 2020 season, just nine pitchers had 11-plus saves, which equates to roughly 30 saves in a 162-game campaign.

With so much uncertainty, fantasy managers may be tempted to go after multiple pitchers from the top two relief tiers, but remember that relievers are a volatile bunch in general. Even closers who appear to be safe picks are still inherently risky, which means there’s more luck involved with drafting relievers than any other position in fantasy.

Of course, it still pays to be prepared. These are the relievers you should know heading into the 2021 season.

Tier 1: Liam Hendriks, Josh Hader

After a breakout season at age 30 in 2019, Hendriks was even better last year, going 14-for-15 in save chances and recording a 1.78 ERA with a 37.0 K-BB% over 25 1/3 innings. Now with a White Sox club that could be an American League powerhouse, Hendriks is the surest bet to lead the Majors in saves, and he could deliver 100-plus strikeouts as well.

Speaking of strikeouts, no reliever has compiled more of them than Hader (380) over the past four years, a span in which the Brewers left-hander has posted a 2.54 ERA. Hader also has registered 50 saves since the beginning of 2019. We're giving a slight edge to Hendriks, but it’s extremely close.

Tier 2: Aroldis Chapman, Edwin Díaz, Raisel Iglesias, James Karinchak, Trevor Rosenthal, Ryan Pressly, Brad Hand

The second tier leads off with the respective closers for the Yankees and Mets, Chapman and Díaz.

Chapman threw only 11 2/3 innings and had three saves after missing the first three weeks while recovering from COVID-19 last season, but he closed out the year by striking out 20 of the final 34 batters he faced. Chapman no longer touches triple-digits on the radar gun regularly, but he has developed a splitter to combat his velocity dip.

Díaz’s second season with the Mets was much better than his first, as he finished 2020 with a 1.75 ERA and 50 K’s in 25 2/3 innings. However, he still has a somewhat tenuous grasp on the closer role after blowing four saves in 10 chances.

Iglesias (Angels), Rosenthal (A’s) and Hand (Nationals) are all expected to close with their new teams in 2021, while Karinchak is the favorite to succeed Hand as the Indians’ ninth-inning man. Karinchak was dominant as a rookie in 2020, striking out 53 of the 109 batters he faced, albeit with 16 walks.

As for Pressly, the 32-year-old could continue to handle closing duties for the Astros after solidifying the role in the wake of Roberto Osuna’s season-ending elbow injury in 2020.

Tier 3: Kenley Jansen, Kirby Yates, Nick Anderson, Alex Colomé, Devin Williams, Craig Kimbrel, Rafael Montero, Archie Bradley

After Jansen’s blown save in Game 4 of the World Series against the Rays, the Dodgers turned to Blake Treinen to close out Game 5 and Julio Urías to finish off the clincher. But Jansen, who has notched 303 saves since the beginning of 2012, is set to retain the closer job to open this season.

Yates had bone spurs removed from his elbow last year and threw just 4 1/3 innings, but he was an elite closer for the Padres in 2019 (1.19 ERA, 41 saves) and could run with the closer role after signing with the Blue Jays in January.

The Rays’ bullpen fluidity -- 13 different pitchers recorded at least one save for the team in 2020 (postseason included) -- hurts Anderson’s fantasy value, but his dominance (1.43 ERA, 45.6 K-BB%) since he joined Tampa Bay prior to the ’19 Trade Deadline, coupled with the likelihood that he’ll see 15 to 20 save chances, gives him a ranking among the top 12 relievers.

Williams didn’t have a save last season, but he was a valuable fantasy commodity nonetheless, posting a 0.33 ERA with a 0.63 WHIP and 53 strikeouts in 27 innings -- a performance that earned him National League Rookie of the Year honors. Even in a setup role, the 26-year-old is worth drafting among the top 175 players.

The Cubs have reinstated Kimbrel as their closer after the veteran recorded a 1.42 ERA with a 38.8 K-BB% over his final 12 2/3 innings last season, and Montero seemingly has a clear path to close after being traded from the Mariners to the Rangers in December. Colomé and Bradley have more competition, but they’re the favorites to lead their new teams -- the Twins and Phillies, respectively -- in saves.

Tier 4: Richard Rodríguez, Jake McGee, Matt Barnes, Will Smith, Drew Pomeranz, Jordan Hicks, Joakim Soria, Mark Melancon, Taylor Rogers, Amir Garrett, Diego Castillo, Giovanny Gallegos, Daniel Bard, Greg Holland, Anthony Bass, José Leclerc, Héctor Neris, Blake Treinen, Zack Britton, Adam Ottavino, Yimi García, Alex Reyes, Freddy Peralta

This tier is made up mostly of pitchers who are either in the mix to close or could be part of a committee. We’ll continue to monitor the news out of Spring Training as Opening Day approaches and update the rankings accordingly.