Jonathan Papelbon’s departure. Heir-apparent Daniel Bard’s shift to starter. Andrew Bailey’s arrival and subsequent thumb injury. Alfredo Aceves‘ tenuous grasp on the closer role.

Needless to say, the Boston Red Sox haven’t seen this much focus on their bullpen since the Theo think-tank rolled out the concept of closer-by-committee in 2003.

At this point, it’s still early. Things will come out in the wash. Someone—be it Bard, Aceves, Franklin Morales, Vicente Padilla, or Mark Melancon—will fall into the role. But, what is the best way of going about determining who that guy is? 

I know, I know, you’re screaming “performance on the field!” But is there a better way than traditional stats—specifically saves—to determine who is the best man for the job? A better way than the eyeball test?

The guys over at FanGraphs think so, and that method comes in the form of a pair of stats called shutdowns (SD) and meltdowns (MD).

To keep it simple, shutdowns and meltdowns are better ways of measuring a reliever’s success because they gauge the percentage a pitcher has added to, or subtracted from, his team’s chance of winning on a given night. Add to the probability of winning more than six percent, and you get a shutdown. Subtract that number or more, and you have a meltdown.

Pretty easy, right? 

Grantland.com’s Jonah Keri wrote a great piece on the subject following Cleveland‘s closer Chris Perez’s ninth-inning meltdown versus the Blue Jays on Opening Day. He explains the stat as such:

By using 6 percent as the cutoff, you get a stat that runs on a similar scale to saves and holds. Elite closers and setup men will rack up 35-40 (or more) shutdowns and very few meltdowns, just as a dominant closer can earn that many saves, while blowing very few.

With that in mind, we’re able to take a better look at just who’s getting it done in the ‘pen. This is because it’s a universal stat—not one that is applied solely to closers. If Franklin Morales is lights out and deserves to slip into the closer role, Bobby Valentine and company will know it regardless of his number of shutdowns and meltdowns. However, these stats—if they catch on—can take some of the pressure away from save itself.

Clearly, without throwing the numbers at you, the Sox bullpen didn’t fare so well on Opening Day in Detroit in the shutdown category. Fine. But it will be interesting to keep an eye on shutdowns and meltdowns over the first few months of the season, to see if it can bring any more clarity to the situation.

But for now, even though Aceves was named the official closer, he really doesn’t get to carry that belt until he earns it. So Melancon, Padilla and Morales all have it in the back of their minds that they could step in at any moment should Aceves lose it. 

But let’s leave Daniel Bard out of it, shall we? He’s a starter, and he’s in that role because he wants to be.

Here’s the thing: If the Bard-as-starter experiment blows up in the Red Sox face, can they really go and insert him into one of the highest-pressure positions on the team, even if he does hit 100 on the gun on occasion? Probably not.

It seems as if they are committed to starting him, and won’t pull him from that role unless he is an abject failure. At that point, they’d have to work on getting his confidence back—not something they want to do night after night in the ninth inning.

As of now, Ben Cherington better hope Aceves and company can hold down the back end of the bullpen—and keep that shutdown category sky-high.

Read more MLB news on BleacherReport.com