Boston's roster is essentially set, in the sense they don't need to add much more. The bullpen has to be sorted out, and just who is catching out of Jarrod Saltalamacchia, Ryan Lavarnway, and David Ross remains to be seen, but as for plugging holes, the Red Sox are finished. There's one outstanding issue, though, that needs attention. And that's to have someone on the roster who can play right field besides Shane Victorino.
While there's a semi-obvious selection on the 40-man already in Ryan Kalish, there are issues with having him around for the job. For one, he's not a great fit for right, given his arm isn't a strength, and the fact Victorino is around means a backup center fielder is already on the 25-man. Then there's the fact that Kalish has just 357 plate appearances over the last two years, thanks to shoulder and neck problems, and subsequent issues surrounding recovery from them. Now 25 years old, and with just one option remaining, Kalish needs to play every day to show the Red Sox he's worth keeping around past 2013 more than he needs to sit on the bench as the team's fifth outfielder, waiting for the game of outfield musical chairs that the disabled list might play.
Daniel Nava isn't a right fielder, but even if he were, Nava is likely the primary left fielder in 2013, with Jonny Gomes getting the short end of that platoon given his affinity for mashing left-handed pitching makes him less important more often. Gomes is the worst defender in the outfield, even when limited to left, so putting him in Fenway's expansive right field is only an attractive option for Boston's opponents.
Bryce Brentz and Juan Carlos Linares haven't hit enough at Triple-A to show they're ready for the majors, and both would require a 40-man spot in order to make it to the majors, anyway. Alex Hassan, already on the 40, likewise has a lot to prove at the plate at Pawtucket, and was certainly not protected from the Rule 5 draft for his poor glove. The answer is going to have to come from outside of the organization.
Options are limited. Austin Kearns hit .245/.366/.367 in part-time duty with the Marlins last season, and might be one of the more impressive of what's left on the open market. He spent much more time in right field when he was younger, with 753 starts in right in his career, but just 11 in 2012. He's a little below-average defensively at this stage, but if he could get on base, consistently, he'd be a solid fill-in option until something better is ready at Pawtucket, be it Kalish, Brentz, Linares, or whoever. Kearns has also featured a reverse split lately, hitting right-handers well, but not southpaws -- Boston could use a bench bat that can hit right-handers, given that on most days it's going to be Gomes as the lone outfielder on the bench, and he's much better against lefties.
Scott Hairston would fit the bill, but he's seeking a two-year deal, and might very well get it considering he's maybe the fourth-best outfielder available via free agency. Hairston would be able to fill-in at center as long as it's something that happens rarely, and he's a serious threat against left-handers. He's not great against righties, but his job wouldn't be to play every day anyway. The issue here, of course, is that Hairston and Gomes are somewhat superfluous offensively, and the team is lacking in hitters that can come in to perform against right-handers late in a game.
There's Ryan Sweeney, whom Boston non-tendered recently. Sweeney can't hit left-handers even a little bit, but he does well enough against righties, and can play any spot in the outfield. He's also shown himself capable of handling Fenway's tough right field, and while he would likely cost seven figures, at least he would be a fit for the job. Yes, the Red Sox non-tendered him, but they also set Scott Atchison loose -- a non-tender isn't necessarily saying you don't want a player. Sweeney was an extra outfielder on the 40 at time when the Red Sox were experiencing a roster crunch. If they can sort out some of their issues and make space, and Sweeney is still around, there would still be a logical place for him in Boston. Whether or not that happens is another question, of course.
And that's about it for potentially useful bench outfielders. Raul Ibanez is barely a left fielder, never mind a right fielder, and players like Endy Chavez barely deserve a non-roster invite at this point. If none of these options are appealing or available to the Red Sox, that last outfielder, one capable of playing right field, is going to need to come from a trade.