Fantasy baseball analyst Dalton Del Don offers us an updated look at the bullpen hierarchy of key teams.

Chicago White Sox

Michael Kopech took a loss during his last appearance, but he remains the favorite to close in an ugly Chicago bullpen. Kopech is a first-round pick and former top SP prospect who’s recording a 34.9 K% after moving to a full-time relief role. His fantasy upside is limited playing for a White Sox team with an MLB-low three wins so far this season, but Kopech (43% rostered) should be added in all fantasy leagues that count saves as a category.

Kansas City Royals

James McArthur remains available in more than 50% of Yahoo leagues despite further entrenching himself as Kansas City’s closer. Since a shaky start to the season, McArthur hasn’t allowed a run while posting a 0.90 WHIP and a 9:1 K:BB ratio over 6.2 innings. He’s also recorded four saves and a win over those six appearances. McArthur sports a 2.26 SIERA and a truly elite CSW (40.0%) that ranks top-five among 221 qualified relievers this year. He looks like one of the best RP waiver wire adds of the season and can be a top-10 fantasy closer moving forward.

Milwaukee Brewers

Abner Uribe racked up three saves over Milwaukee’s first four games of the season, but he’s yet to record one since. He entered during the fourth inning of Tuesday’s loss and then set up a Joel Payamps save Wednesday. Payamps was blown up during one outing, but he’s been scoreless over eight innings otherwise. Trevor Megill will eventually also enter the picture, but Payamps sports a 1.57 FIP and a 0.68 WHIP on the season and appears to be the current favorite to close in Milwaukee, so he needs to be added if you’re looking for saves. He’s available in nearly 70% of Yahoo leagues.

Minnesota Twins

Griffin Jax hasn't recorded a save since his first appearance of the season, as he wasn't used as a traditional closer with Jhoan Duran sidelined as fantasy managers hoped. Steven Okert and Cole Sands have recorded the same number of saves as Jax, and Duran is reportedly healthy and set to return by the end of the month. Jax can be dropped in most fantasy leagues.

Philadelphia Phillies

The Phillies are using a committee to close based on matchups, but it may be worth noting José Alvarado has some ugly peripherals. He ranks bottom-15 among 221 relievers in BB% (20.0), and his 7.6 SwStr% isn't much better. Jeff Hoffman will continue to see late-game opportunities, and the newly recalled Orion Kerkering remains the favorite to lead the team in saves in the second half of the season. Both Hoffman (10% rostered) and Kerkering (18%) are widely available in Yahoo leagues.

Seattle Mariners

Andrés Muñoz was drafted as a top-10 fantasy closer, but he hasn’t seen a save opportunity since April 6. Injuries in Seattle’s bullpen have pushed Muñoz into a high-leverage role, including him entering in the seventh inning during his last appearance. Muñoz remains the clear Mariners’ RP to roster in fantasy leagues, but his usage has been incredibly disappointing. Hopefully Matt Brash’s eventual return leads to Muñoz closing more.

Tampa Bay Rays

Pete Fairbanks has lost a couple of save opportunities thanks to the balls in Coors Field and has struggled badly this season (his 7.2 SwStr% is easily a career low). But he gives great interviews, and Tampa Bay still has confidence in him. Fairbanks has uncharacteristically struggled with control (his 58.6 K% is down about 10% from the last two seasons), but he's likely to bounce back assuming he's healthy. His .444 BABIP is sure to regress as well, and Fairbanks remains the favorite to close in Tampa Bay.

Texas Rangers

Kirby Yates has overtaken a struggling José Leclerc (2.2 K-BB%) and is plenty capable of keeping the closer's job over the rest of the season, so he needs to be added in any fantasy league in which he remains available.