Let's assemble the 2015 Red Sox pitching staff

The Red Sox have a full 40-man roster, something we were reminded of on Wednesday when Dan Butler was designated for assignment to make room for Craig Breslow. Butler is a potentially useful player, too, which goes to show you that not only is Boston's 40-man full, but it's also loaded with talent. Because of this, at this stage of the offseason, improving the 40 isn't the main focus: whittling down what already exists to fit onto the 25-man in-season roster is.

There are a whole lot of moving pieces on this roster, and therefore there are a number of acceptable variations of it the Sox could trot out on Opening Day 2015. By breaking things down, we can assemble a 25-man roster -- and some alternate possibilities -- from what the Sox have right now. We'll assume the Red Sox will utilize your standard nine starting position players, 12 pitchers, and four bench players to create their 25-man. Today, we'll worry about figuring out who those 12 pitchers are going to be.

The rotation, barring the addition of another starter through trade or signing, is set. In no particular order, Clay Buchholz, Rick Porcello, Wade Miley, Justin Masterson, and Joe Kelly will be Boston's five starters. That leaves seven spots open for relievers, which is where things get a little trickier. These are the other pitchers currently on Boston's 40-man roster:

• Matt Barnes
• Craig Breslow
• Drake Britton
• Edwin Escobar
• Heath Hembree
• Tommy Layne
• Edward Mujica
• Anthony Ranaudo
• Eduardo Rodriguez
• Zeke Spruill
• Junichi Tazawa
• Koji Uehara
• Anthony Varvaro
• Brandon Workman
• Steven Wright

A few of those can be subtracted from the mix easily. Eduardo Rodriguez and Matt Barnes are still 100 percent starting pitching prospects, and have options remaining. Steven Wright has an option left, and can work as depth for either the rotation or bullpen while at Triple-A. Tommy Layne, Zeke Spruill, and Heath Hembree also have options, so they can be stashed in Pawtucket until they're needed, too. Those last four could all be useful pieces to different degrees, but no one is going to miss them if they begin (and end) the year in Rhode Island.

The locks for the pen are closer Koji Uehara, setup men Junichi Tazawa and Edward Mujica, and then likely Craig Breslow by virtue of being the only lefty on the roster with any real success in the majors the last few years. Drake Britton could join up, as he's a southpaw who is out of options, but he also pitched like garbage in the minors last year. There's a chance the Sox try to pass him through waivers sometime in the next couple months just to get him off of the 40-man. Edwin Escobar could be sent back to Triple-A with his final option, but as Breslow is currently the top lefty for the Sox and the likes of Britton and Layne are in-house alternatives, that's maybe not such a good idea. Escobar might be a stretch as a useful big-league starter, but the lefty could thrive in a full-time relief role, and as soon as Opening Day.

Assuming the Sox will risk losing Britton and will instead put Escobar in the majors means there are two spots left, probably both for right-handers. One of those could go to Anthony Varvaro, a strong sixth inning option recently scooped up off waivers from the Braves. The other spot is down to Anthony Ranaudo or Brandon Workman, whichever of the two the Red Sox feel is ready to commit to relief full-time. There might not be a wrong answer to this, as it's very likely that's the role for both eventually, but Workman already has some experience in the pen so he might be the easier transition. Whichever of the two ends up back in Pawtucket would join a rotation that also includes Rodriguez, Barnes, Henry Owens, and Brian Johnson, and likely do so as their last-ditch effort to remain a starter.

So, a rotation of Buchholz, Porcello, Miley, Masterson, and Kelly, followed by a bullpen of Koji, Tazawa, Mujica, Breslow, Escobar, Varvaro, and Workman. That's 12! We're not quite finished, though, because there are other possibilities to consider that could occur between now and Opening Day.

Let's say the Red Sox trade for an upgrade in the rotation, or sign James Shields. That would push Joe Kelly to the bullpen, leaving him as a right-handed swingman who is both capable of setup and long relief work when needed, while also acting as perpetual insurance against both injury and any disappointment that comes from relying on both Buchholz and Masterson. It would also likely bump Workman to Triple-A, and probably their bullpen, so he would be ready to step in should Kelly need to return to his starting role.

Or, maybe realizing that Workman isn't an encouraging name in a bullpen that also has such huge questions from the left side, the Sox go out and re-sign Burke Badenhop to strengthen things from the right. They could also go out and find a lefty reliever, through signing or trade. It's worth pointing out that the lefty reliever market is all but closed up as of this writing, though: there's a reason the Sox brought Breslow back even after a disappointing 2014. If Franklin Morales can be coaxed back into a relief role, or the Sox want to roll the dice on Sean Burnett coming back healthy from Tommy John by midseason, though, there are a couple options worth exploring.

It seems as if the bullpen could use another arm one way or another, but if the Sox can't find one, it's also not the end of the world. They have depth in Triple-A if needed, and if someone like Eduardo Rodriguez or Henry Owens pushes the issue, maybe Kelly joins the pen by midseason, anyway. There are certainly worse fates than starting the season with the back-end trio of Koji, Tazawa, and Mujica, but the Sox are also in a position to easily upgrade over the next couple of months if such an opportunity presents itself.