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Atlanta Braves reliever Peter Moylan was one of the most valuable members of any team's bullpen last year.

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Middle relief is never a sure thing in baseball. The Atlanta Braves have been lucky in the past to have cobbled together good middle relief corps. They haven't been so lucky the last few years, but last year they did a decent job of assembling good middle relievers while working around some injuries.

The most striking thing about the 2009 middle relief crew was how fast the team was to make a change early in the year. The Braves hadn't broke camp a week when they released Blaine Boyer after two (out of three) disastrous outings. Blaine bounced around the rest of the season, ultimately finding some success (or luck) in Arizona. The Braves were also quick to cut ties with Jeff Bennett after he went kung-fu on the clubhouse wall.

Peter Moylan

Perhaps the rock of the 2009 bullpen, Peter Moylan appeared in 87 games only a year removed from Tommy John surgery. He got off to a rough start, but continued to battle, and posted a 1.00 ERA in the second half of the season. He gave Bobby Cox the luxury of having a second setup man, and his 25 holds led the team and ranked 6th in the NL.

Going back to the 87 games he appeared in, that should raise some alarms, but Moylan insists he likes to pitch that much and many say that his arm angle puts less strain on the elbow than an overhand motion. Those 87 games ranked one game behind the NL leader in appearances for a pitcher, and the Braves had 4 relievers in the top-10 in appearances.

Eric O'Flaherty / Boone Logan

One of those relievers who was in the top-10 in appearances was Eric O'Flaherty. The lefty specialist appeared in 77 games (56.1 innings pitched) and put in his best work as a major leaguer. The Braves got him off the waiver wire from Seattle last off-season, and he beat out Boone Logan in spring training for the LOOGY role. A minor pick up at the time, his good season makes that move look genius -- getting a reliever like that without having to give up anything.

Boone Logan came over as part of the Javier Vazquez trade. He was called up several times in 2009, but had spotty success while being used rather sparingly by Cox.

Here is a breakdown of all the lefty relievers on the Braves in 2009, and how they did versus left and right-handed batters:

O'Flaherty was pretty close to Gonzalez in handling lefties, but Logan wasn't that far away either. The big difference between O'Flaherty and Logan comes when they're facing right-handed hitters, with Eric having the clear advantage in that department. The Braves will probably want to keep all the depth they can, but Logan is out of options and arbitration eligible this year, so a non-tender might be in his future.

Kris Medlen

While Medlen posted a respectable 4.26 ERA for a rookie, his ERA as a reliever was even better at 3.47. He struck out more than a batter per inning in relief and gave up less than a hit per inning while keeping his walks in check. He was used inconsistently at times, getting long rests only to pitch on consecutive days. This unfamiliarity with the major league bullpen role caused Medlen to admittedly undergo some growing pains, but his work ethic kept his spirits up and his mind ready for any situation.

He could certainly move into a setup role next year, and may become one of the more indispensable members of the Atlanta pen. With the Atlanta rotation at 120% capacity, there's little chance that he would move back to a starting role, but his familiarity with starting may make him an ideal emergency swing man -- further increasing his value to the bullpen and the team.

Manny Acosta

Here are Acosta's ERAs the last three years: 

2007 - 2.28
2008 - 3.57
2009 - 4.34

Meanwhile his FIP has hovered around 4.77, and has never been below 4.25, so that should tell us that Manny is either getting real lucky or he's getting bailed out by other Atlanta relievers -- either way it seems to be catching up to him. He is becoming more and more worthless, and that tells me his spot in the pen is in question.

Others

Jo-Jo Reyes and James Parr could find some time in the bullpen in 2010, though neither is ideal for the role. Luis Valdez is doing well in winter ball, and he could play a prominent role in the pen as well. I wondered why the Braves didn't use him more this year, especially towards the end, but maybe they wanted him to get work in winter ball and not the majors.

As always, there is a lot of work to be done this off-season to bolster the Atlanta bullpen.