We're only six weeks into the 2011 season but already several bullpens have reshuffled. Let's take a quick look around the league at some of those who couldn't hold on to the closer's role.

Most recently, the Houston Astros placed Brandon Lyon on the disabled list, paving the way for Mark Melancon to pick up some saves. Lyon was diagnosed with bicep tendinitis and a partial rotator cuff tear, which might explain his bloated 7.15 ERA. Melancon has a closer's arsenal (8.5 K/9) and is a good bet to hold on to the job even after Lyon returns.

After Drew Storen struggled in spring training, Nationals manager Jim Riggleman named Sean Burnett the closer in Washington. Storen's stuff returned in the regular season (0.48 ERA and seven saves), but Riggleman has still shown a willingness to use Burnett in certain save situations -- such as last Friday. Those chasing saves in deep NL-only leagues should hold on to Burnett.

Joe Nathan began the season as a feel-good story, but it quickly became clear he was not the same pitcher who saved 246 games between 2004-09. Matt Capps immediately took over ninth-inning duties, but his peripherals (3.77 K/9 and 1.26 HR/9) suggest he's not long for the role. Glen Perkins has been stellar in the eighth, and if Nathan doesn't regain his form, Perkins might get a shot a closing in the Twin Cities.

In Toronto, Frank Francisco began the season on the DL, which gave Jon Rauch an opportunity to close. Rauch was good (3.75 ERA and five saves) but not great, and a recent cold streak (three earned runs in his last 3.1 innings) opened up the door for Francisco. The Blue Jays didn't acquire Francisco to pitch the eighth, so he should get the bulk of saves going forward.

How did the rest of the major league bullpens fare this week? Let's take a look around the league:

Heath Bell Mariano Rivera Brian Wilson Jonathan Papelbon

Bell blew his first save in 42 chances on Friday, thanks in large part to a throwing error by Chase Headley. When his infielders aren't throwing away outs, Bell remains the best closer in fantasy baseball. ... Are the Giants overusing Wilson? He pitched five times last week, and with one injury already in the books for 2011, his usage bears watching.

Neftali Feliz Huston Street Francisco Rodriguez Carlos Marmol Chris Perez Francisco Cordero Joel Hanrahan Joakim Soria

Feliz's DL-stint was precautionary and he was throwing 100-mph heat during his rehab stint. Insert him into your lineup immediately. ... K-Rod notched three saves last week, but he never makes it easy on himself. He walks a batter or gives up a hit in almost every appearance and his atrocious 1.88 WHIP attests to that. Maybe he needs the added pressure of base runners.

Leo Nunez Drew Storen Jose Valverde Craig Kimbrel J.J. Putz Brandon League John Axford Kyle Farnsworth

Nunez has been sloppier as of late (three earned runs and four walks in his last 4.2 innings) but he leads the NL with 11 saves. He'll need to rein in the long ball (1.08 HR/9) if he wants to keep the role all season long. ... Valverde bounced back from a blown save on May 5 by striking out the side for a save against Toronto on May 8. He's got great peripherals (3.0 K/BB) and should surpass his save total from last year (26).

Ryan Madson Sergio Santos Matt Capps Frank Francisco Kevin Gregg Jordan Walden Mark Melancon Fernando Salas/Eduardo Sanchez Vicente Padilla Brian Fuentes

Since Jose Contreras went on the DL in late-April, Madson has had no trouble locking down the ninth inning. He's given up zero runs and only four hits in 7.0 innings as the closer. The role is looking his to lose even when Contreras comes back. ... Santos hasn't given up a run all season and his peripherals are stellar (3.16 K/BB). He's got a strong hold on the closer's role, and it's just a shame the White Sox aren't playing better. ... The Cardinals closer-by-committee continues to frustrate. Tony La Russa trusts both Salas (three saves and 1.42 ERA) and Sanchez (three saves and 2.77 ERA), but neither looks ready to emerge as the favorite. If you're going to speculate, Salas has more experience and better control.

Jose Contreras/ Brad Lidge David Aardsma Andrew Bailey

Aardsma's rehab is currently on hold after he felt soreness in his throwing arm. The latest injury is a disconcerting development given that Aardsma's DL-stint was related to his hip. ... Bailey's rehab continues to progress and he should slide right into the closer's role once activated.

Backups who will ensure you're banking saves even if your closer goes down:

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