The latest change came in Los Angeles on Monday, when the Dodgers took the closer's job from Javy Guerra and handed it to Kenley Jansen. During his brief time as the closer this year, Guerra put together a 1-3 record, 5.84 ERA and eight saves in 11 opportunities.
"More than anything, these guys want to win," Dodgers manager Don Mattingly said. "Javy isn't wanting to not get guys out. In the end, I think, he just wants to do what is best for the team, understanding he hasn't been getting guys out at the end of the games."
Miami had to make a similar decision with high-profile free agent Heath Bell, one of the team's three big acquisitions at the Winter Meetings. The club sought the elusive "proven closer" to bolster its bullpen and lock down saves in its new ballpark, but Bell got off to a disastrous start.
The 34-year-old right-hander has an 0-3 record, 11.42 ERA and three saves in seven opportunities. He's walked 10, two of them intentionally, while recording only six strikeouts. Despite having given Bell a three-year, $27 million contract, the Marlins opted to temporarily demote him and give Steve Cishek a shot in the ninth inning.
"We're going to move [Bell] down for a few days to get him back on track," Marlins manager Ozzie Guillen said on Saturday. "It's not like we're removing him from his job. I made it clear to him that if we're going to be the club we should be, it's easier for him to be where he's supposed to be."
The Angels and Cubs had to do the same with Jordan Walden and Carlos Marmol, respectively. Walden got off to a rocky start that was punctuated by a walk-off homer off the bat of Rays outfielder Brandon Allen on April 26. Marmol's ninth-inning meltdown on Thursday, when he walked three of the five batters he faced in a game the Cubs went on to lose, was the final straw for the erratic right-hander.
"Who knows whether it's mechanical, mental," Cubs manager Dale Sveum said on Friday. "His side sessions are good. The game speeds up a little bit and gets pumping, [and] everything just breaks down a little bit. That's why, as much as anything, we have to make him a productive pitcher in whatever role it is for us."
The rest of the changes have been driven by the physical, from Ryan Madson's season-ending Tommy John surgery during Spring Training to Mariano Rivera's recent ACL tear.
The bullpens of the American League East have been especially ravaged by injuries, with the Yankees, Red Sox, Rays and Blue Jays all without the closers they had when spring began. Rivera tore the ACL and meniscus in his right knee while shagging fly balls at Kauffman Stadium in Kansas City on Thursday, elevating David Robertson and Rafael Soriano into more prominent roles with the future Hall of Famer done for the year.
The Red Sox have been without Andrew Bailey all season due to an injured right thumb that required surgery, and their bullpen limped out of the gate as a result. Blue Jays closer Sergio Santos has been out since April 21 with inflammation in his right shoulder.
And the Rays will be without Kyle Farnsworth, who saved 25 games in 2011, until at least June because of a strained right elbow. Tampa Bay manager Joe Maddon never officially named Farnsworth the closer last season and hasn't done the same with Fernando Rodney now, but Rodney may have earned the job for good with a brilliant start.
"He just brings that little bit of crazy that you need on the mound in the ninth inning," Rays utility man Ben Zobrist said of Rodney. "You've got to have somebody that's not fully seeing the situation and kind of freaking out about it."
The Royals have found a suitable replacement for Joakim Soria -- done for the season following Tommy John surgery on his right elbow -- in Jonathan Broxton, who has a 1.69 ERA and six saves in seven chances. The same can be said for the Nationals, who have seen Henry Rodriguez post six saves, a 2.84 ERA and a 1.105 WHIP through 12 2/3 innings of work as they await the return of Drew Storen (surgery on right elbow).
Out west, the Padres are without new closer Huston Street, whom they acquired via trade this winter, due to a strained right lat. Street didn't expect the strain to be a major injury, but he nonetheless joined many of his fellow closers on the DL.
One of them, Giants closer Brian Wilson, has become uncomfortably familiar with the DL since last year. The bearded right-hander was banged up toward the end of 2011 and felt he was on "borrowed time" following San Francisco's World Series run in 2010.
When he went down again with an injured right elbow in April, the only solution was a second Tommy John surgery. As they did last September, the Giants have primarily relied on Santiago Casilla as their closer.
"The job Casilla has done really lightens the load on the rest of us. We don't have to worry about the ninth inning," Giants reliever Sergio Romo told reporters on Monday. "All we have to do is be the same complement to him that we were to Wilson."