FORT MYERS, Fla. -- It is, said Bobby Valentine, the most befuddling aspect of the Red Sox roster. There is no part of the team that has many question marks as the bullpen.

"I don’t know the whole grouping out there yet," said Valentine. "I think the most perplexing situation we have right now is that grouping. It’s compounded by the number of starters we have. It’s a very interesting situation, challenging situation, that is about ready to get sorted out in the first stages."

The Sox will, in all likelihood, carry seven relievers to open the season. It is possible that for the first few days of 2012, the team could have eight members of its bullpen given that the team won't need a fifth starter until its sixth game of the season, on April 11 against the Blue Jays. That being the case, if the Sox identify one of their minor league free agents -- presumably either Aaron Cook or Vicente Padilla -- as the fifth starter to begin the year, they could let him open the year with a start for Pawtucket and then wait until the 11th to add him to the big league roster.

Right now, the only known members of the Red Sox bullpen are Andrew Bailey (who will be the closer, assuming that he suffers no setbacks in his return from what was considered a minor lat injury) and right-hander Mark Melancon. Beyond that, there are five or even six spots that lack definition.

Here is a look at the candidates to fill out the bullpen:

THE FIXTURES

RHP Andrew Bailey
Spring: No appearances

Bailey was acquired from the A's as the likely closer, and the Sox expect to use him for the ninth inning. He is set to make his Grapefruit League debut on Monday, and the Sox plan for him to throw seven innings this spring.

RHP Mark Melancon
Spring: 2 innings, 2 hits, 1 run, 1 walk, 1 strikeout

Melancon, who closed last year for the Astros, will be a key setup man, though it remains to be seen precisely how he is used.

POTENTIAL STARTERS WHO CAN RELIEVE

The Sox currently have five pitchers who are competing for the last two spots in their rotation, with a potential sixth candidate just behind them in the person of right-hander Aaron Cook. All except Cook could be bullpen candidates if the team does not open the year with them in the rotation.

Thus, there is a strong chance that three to four relievers could come from the following group:

RHP Alfredo Aceves
Spring: 5 innings, 2 hits, 0 runs, 0 walks, 4 strikeouts

RHP Daniel Bard
Spring: 5 innings, 2 hits, 0 runs, 3 walks, 3 strikeouts

LHP Felix Doubront
Spring: 2 innings, 3 hits, 2 runs, 3 walks, 2 strikeouts

LHP Andrew Miller
Spring: 2 innings, 0 hits, 0 runs, 1 walk, 3 strikeouts

RHP Vicente Padilla
Spring: 4 innings, 8 hits, 4 runs, 0 walks, 2 strikeouts

Both Daniel Bard and Alfredo Aceves can be impact relievers, though both are being stretched out right now in the competition for the fourth and fifth starters' spots. In many ways, it would be an upset if a) neither Bard nor Aceves ended up in the rotation and b) both Bard and Aceves ended up in the rotation.

At this point, it is difficult to imagine the Sox turning away from the idea of having Bard in the rotation, and so by default, Aceves would seem more likely to move to the bullpen.

BUT… two things could conspire to change that blueprint and result in the upset of having both Bard and Aceves in the rotation. To this point, Aceves has been as impressive as any starter in camp with the way that he’s carved the strike zone with four pitches. If he separates himself from the other rotation candidates, then he might be too valuable to ignore as a rotation option.

“He’s someone we have to really seriously look at as a possible guy in that starting rotation,” said pitching coach Bob McClure. Now he’s so versatile that I’m not saying it’s gonna mess with him that he’ll end up in the bullpen because to me, you win with starting pitching.

“Is it nice to have a guy like him in the ‘pen? Sure it would. It would be nicer to have a guy like him starting and a guy like him in the bullpen. But shoot, on every fifth day, you’ve got a guy who can pitch like that, go seven innings, eight innings, that can pitch every day, that’s nice to have.

“Unfortunately, and it happens to a lot of guys -- it happened to myself as well; when I came up, I was a starter and they put me in the pen -- you do OK and the next thing you know, you’re still in the bullpen and you’ve been wanting to start for two or three years. He’s in that boat. He’s done so well that everyone looks at him like, well, shoot, he’s so valuable there but I don’t know what’s more valuable than starting pitching, other than maybe a closer.

“I think Texas has shown that, to have five good starters, so you’re not keeping your fingers crossed, is this guy going to throw strikes today? If you’ve got five solid guys with a chance to win every single day, to me, that’s just more important.”

But, McClure’s suggestion that it would be ideal to have an Aceves-like pitcher in both the rotation and bullpen suggests that his fate will be linked to whether the Sox can find one of the other pitchers in the rotation competition who can become a versatile swing-man in the bullpen.

Left-handers Andrew Miller and Felix Doubront find themselves in a shared boat. Both are out of minor league options, and so the Sox must either keep them on the big league roster or part with them. Both are being stretched out for the rotation (though Miller suffered a minor setback when he experienced some discomfort just above his elbow this week).

Doubront has a diverse pitch mix and a track record of solid command in the minors. Pitching coach Bob McClure said that his first impression of the left-hander is that he's a strike thrower.

Miller, on the other hand, has electrifying stuff (as manager Bobby Valentine pointed out last week, you can count on one hand the number of left-handers who are as tall as the 6-foot-7 Miller and who can touch the mid-90s with their fastballs) but command that, through his career, has been extremely inconsistent. Assuming that Miller is healthy, one or both of the left-handers will likely end up in the bullpen.

Vicente Padilla signed a minor league deal with the Sox in the offseason that included incentives structured around the idea that he could either start or relieve. He spent a brief spell as the Dodgers closer last year. While he's being stretched out now, if he doesn't win the fifth starter's spot, he could well land back in the bullpen.

PITCHERS WHO ARE SOLELY RELIEF CANDIDATES ON THE 40-MAN ROSTER

RHP Matt Albers
Spring: 1 inning, 1 hit, 0 runs, 1 walk, 0 strikeouts

RHP Michael Bowden
Spring: 2 2/3 innings, 0 hits, 0 runs, 0 walks, 2 strikeouts

RHP Chris Carpenter
Spring: 1 inning, 2 hits, 4 runs, 3 walks, 1 strikeout

RHP Junichi Tazawa
Spring: 2 innings, 2 hits, 0 runs, 2 walks, 0 strikeouts

Right-hander Matt Albers was one of the most valuable Red Sox relievers through last July before his struggles in August and September contributed to instability at the back end of the game. He had a 2.09 ERA through 35 games (43 innings) at the trade deadline, but then gave up 24 runs in 21 2/3 innings in August and September. Albers, who is out of options, would make a big league salary of $1.075 million.

Right-hander Michael Bowden, a sandwich pick of the Red Sox in 2005, is likewise out of options. He has made a strong first impression on new Sox manager Bobby Valentine, who said that it will be a priority to see more of Bowden this spring. For more on the right-hander, who dominated righties to the tune of a .121 average against last year in Triple-A, click here.

Right-hander Junichi Tazawa, now fully recovered from his 2010 Tommy John surgery, is being evaluated solely as a bullpen candidate. He has two minor league options remaining.

The Sox like Tazawa’s fastball/slider/splitter combination for the bullpen. He is almost certain to contribute in the majors at some point this year, although given that he can be sent back down to the minors, the most likely scenario for the 24-year-old would have him opening the year in Triple-A (barring injuries to other bullpen candidates); it's also worth noting that he hasn't been terrifically sharp in his early outings of the spring.

Right-hander Chris Carpenter, acquired from the Cubs as compensation for the departure of Theo Epstein, has three options remaining. He has an electric arm, but he's still working to refine his command to the point where he can emerge as a reliable reliever. His ability to hit triple digits on the radar gun virtually ensures that he'll be in the majors at some point, but probably not to start the year.

ON 40-MAN ROSTER, BUT INJURED AND LIKELY TO START YEAR ON DL

LHP Rich Hill

RHP Bobby Jenks

LHP Frankin Morales

Left-hander Franklin Morales was shut down due to shoulder weakness early in Red Sox camp, and he is only now resuming throwing. He showed some solid signs with the Sox in the majors last year, most notably, a 31-to-11 strikeout-to-walk ratio in 32 1/3 innings and a gutsy, two-inning, 44-pitch relief appearance in which he claimed what was, at the time, a huge win against the Yankees in New York in the season's final week.

There's a good chance he'll open the year on the DL, but his mid-90s fastball and swing-and-miss breaking ball make him a likely contributor whenever he’s had a normal progression. Manager Bobby Valentine anticipates that will occur early in the year.

“There’s a plan for him. It’s not unreasonable to think he’s going to be charging hard when the season begins,” said Valentine. “Maybe not the first day of the season but the beginning part of the season.”

Left-hander Rich Hill has moved at a faster pace in his return from Tommy John surgery than anyone could have rightly expected. Even so, right now, the Sox are targeting late-April as the most likely time for him to pitch in minor league games, so it would be difficult to imagine that he will be pitching in the majors before May.

Right-hander Bobby Jenks has already been placed on the 60-day disabled list, and if he pitches at all this year, it would not be until late in the season.

NON-ROSTER CANDIDATE

RHP Scott Atchison
Spring: 2 innings, 2 hits, 1 run, 2 walks, 2 strikeouts

LHP Jesse Carlson
Spring: 2 innings, 1 hit, 1 run, 1 walk, 1 strikeout

RHP Justin Germano
Spring: 2 innings, 1 hit, 0 runs, 0 walks, 0 strikeouts

RHP Doug Mathis
Spring: 2 innings, 1 hit, 0 runs, 0 walks, 1 strikeout

LHP Justin Thomas
Spring: 2 innings, 2 hits, 1 run, 1 walk, 0 strikeouts

RHP Alex Wilson
Spring: 1 inning, 5 hits, 4 runs, 2 walks, 0 strikeouts

Scott Atchison represents a known quantity for the Red Sox. In the last two years, he has a 4.08 ERA in 60 games. He has shown the ability to serve as a long man and also to pitch credibly in shorter stints, and he's particularly tough on right-handers.

The Sox like Atchison in no small part because he’s a strike-thrower – something that does allow him to assume some bulk innings in long relief – and they consider Germano and Mathis to be cut from a similar mold. Germano leans on a two-seamer in the high-80s, which he complements with a curve and changeup, while Mathis  was the first name Valentine mentioned when asked last week about sleeper players in camp.

The Sox are intrigued by Carlson’s stuff and delivery, which seems like it should give left-handers fits, but after he missed all of last season due to shoulder surgery, he will likely need time in the minors to build back up to the point where he’d be a big league consideration.

That leaves Thomas as the left-hander who will get the longest look for a roster spot among the non-roster invitees. Thomas has been hit hard in 20 big league games with the Mariners and Pirates, but in the last two years in Triple-A, he has a 110-to-34 strikeout-to-walk rate in 123 2/3 innings.

Alex Wilson, 25, represents a high-ceiling option for the Sox. The likelihood is that, after making four starts in Triple-A last year, he will open the year as a starter in the PawSox rotation and provide the Sox with potential starting depth for at least part of the year. But, he could represent an option for a bullpen reinforcement later in the year.

FINAL THOUGHT

The Red Sox, mindful of the attrition that a season takes on a pitching staff, typically like to maximize their organizational pitching depth as they break camp. That means that unless certain pitchers achieve significant separation from the pack during camp, if talent levels are bunched together, the team will prioritize keeping players who are out of options and/or have early-season opt-outs in the majors.

So, if the Sox wanted to keep the maximum number of pitchers, a 12-man pitching staff might look something like this:

ROTATION

LHP Jon Lester
RHP Josh Beckett
RHP Clay Buchholz
RHP Daniel Bard (not a given, but a probable outcome)
RHP Alfredo Aceves or LHP Felix Doubront (out of options)

BULLPEN

RHP Andrew Bailey
RHP Mark Melancon
RHP Alfredo Aceves or LHP Felix Doubront (out of options)
RHP Matt Albers (out of options)
RHP Vicente Padilla (minor league contact with opt-out)
LHP Andrew Miller (out of options)
RHP Michael Bowden (out of options)

That, however, does nothing to explain how the various pitchers in the bullpen would be used. Moreover, such a sketch is merely a theoretical exercise right now, since it is too early in camp to draw any conclusions about favorites for the staff. The Sox remain open-minded as they sift through the various candidates for their rotation and bullpen. And, such a structure would have to be reconfigured if/when Morales and/or Cook join the roster.

All of that being the case, the evaluation process remains an unusually complex one given the intertwined nature of the rotation and bullpen.

“There’s so many guys vying for the fourth and fifth spot right now, it’s a little different,” said McClure. “It’s a puzzle that I haven’t quite figured out yet.”

For now, there are plenty of pieces for the puzzle, but it likely will require the duration of spring training to figure out how they fit.