Even after designating players for assignment and non-tendering others, the Red Sox have 13 relievers on their 40-man roster. That doesn't include the recently signed Koji Uehara, so, in reality, Boston has 14 relievers to choose from at the moment.
Major-league pitching staffs usually top out at 13 in total, including five starters, but even that's considered pushing it. Using 12 for most of the year is the general practice, so it's clear that the Red Sox need to do some additional shuffling and winnowing to make their current situation workable. Who are the seven relievers they're most-likely to assemble in the majors, and what's going to happen to the other half of the bunch?
There are obvious options for inclusion on the big-league staff. Andrew Bailey, assuming health, is likely to be the team's closer. Junichi Tazawa and Koji Uehara are the most-likely setup men. Mark Melancon is now out of options, and looked to be getting on track at the end of last season, so he, along with Craig Breslow, are very likely to be middle relievers. That puts the bullpen at five, leaving room to store left-handed reliever and starting pitching depth Franklin Morales, as well as one other arm.
It was easy enough to get to six, but who is lucky number seven? Let's start with who it doesn't have to be. Pedro Beato has two options remaining, so he can be sent to Pawtucket for the next two years if need be. Sandy Rosario likewise can be sent to the minors rather than the majors, and therefore there's no reason to force him onto the big-league roster. Alex Wilson was just added to the 40-man, so he has all of his options intact. Chris Carpenter has one option remaining, and since elbow surgery limited him in 2012, starting off with constant reps in the minors might be best for him anyway.
That still leaves four potentials for that last spot. Andrew Miller, Alfredo Aceves, Daniel Bard, and Clayton Mortensen are all candidates to be in the majors with the Red Sox, but, due to their situations, might also be trade bait instead. Someone -- or someones -- from the 40-man roster are going to need to be dealt or cut in the coming weeks, as Boston has three players unofficially signed in Alfredo Aceves, Shane Victorino, and Uehara who will all require placement on a 40-man roster with just one open slot on it. Relievers aren't the only thing the Red Sox can move, but it's a place of depth and the easiest area from which to do so.
In theory, Bard could start the season with Pawtucket. While it's been more than three years since he arrived in the majors, meaning other teams could put in a claim for him when he is optioned, it's considered poor transaction etiquette to do so, and the Red Sox already pushed him through that way once last summer. He has two options remaining, and while the talent that was there in the past makes him an attractive pluck for other clubs, Boston could pull him back. As the end of his 2012 didn't exactly inspire confidence in his being ready, other clubs might not be all that interested in using a big-league spot on him anyway.
The Red Sox have spring training still to see where he is and where they can get him to before Opening Day arrives, but if he's not where he needs to be, Pawtucket is a realistic option. Because of this, Bard sort of straddles the line between being an option for the seventh spot, and not needing to be there. That leaves Aceves, Miller, and Mortensen, if you want to be cautious about Bard's resurgence and role.
Aceves has an option left, but that's opening a can of tantrum-y worms that would most likely result in Boston dealing him rather than even bothering with the demotion. Both Mortensen and Miller qualified to have four options rather than the standard three, and both have used up all of them. Each of those pitchers performed well enough in 2012 that they can't be designated for assignment to remove them from the 40 without losing them to another team.
Miller might have the advantage as a lefty. Morales and Breslow are both left-handed, but part of the reasoning for acquiring Breslow in the first place was so that, should Morales start, there are still two left-handed options in the bullpen. Changing Miller's mechanics didn't make him into the dominant force he was believed to be capable of back when he was drafted in the first round of the 2006 draft, but it did help him with both his command and control, and resulted in a career-best strikeout-to-walk ratio and 131 ERA+. That's reason to include him in a trade, should Boston be able to get something else they could use, but it's also a reason to hold on to him if there's space.
While Miller might be a step up due to his handedness, dreams of Aceves putting together another 2011 campaign could be what makes him the last piece in the bullpen puzzle. He's not great starting depth, but he's still depth, and if he can throw 90-100 innings in relief, then he's going to be hugely valuable, more so than Miller could hope to be in his role as a lefty killer. The Red Sox need to get Aceves to stop trying to blow it by hitters, instead using his command of a low-90s fastball to let hitters do the work for him, as he had done prior to becoming the team's closer. If he can do that once more, he'll be a different -- and productive -- hurler once more, likely one with the kind of rubber arm that made him appealing in the past. Of the three, his upside is the greatest, but he also has clear issues that have led to his personality essentially being put on probation by new manager John Farrell, so he might be out the door before the season begins depending on how that relationship evolves.
As for Mortensen, he might be the odd man out.Part of what made him so valuable last season was his ability to bounce between the majors and minors as necessary. As he's out of options, that can no longer be the case. In reality, Mortensen is a useful low-leverage reliever capable of soaking up innings. Aceves can do that, and with a higher ceiling to boot, and it's not as if the Red Sox lack other relievers they can use in the same manner -- and those pitchers do still have options.
Throw in that part of his success from 2012 had a lot to do with an unsustainable batting average on balls in play of .238 -- a figure that led to his stranding 88 percent of his baserunners, or, a good 15 percentage points more than average -- and there's even more reason to not force a role in next season's bullpen. Mortensen can likely be useful with the right club, one bereft of bullpen depth, but the Red Sox are most-likely not that team.
There are trade opportunities out there for Boston to make room this winter -- pair a reliever or two with a catcher, or if a Jacoby Ellsbury trade actually goes down -- but it's likely to be a slow process. You can guess that the Red Sox are working on it, though, especially since they have very intentionally not made their three most-significant free agent hauls of the winter official just yet.