Apparently, the outfield isn't actually full yet
Boston signed Shane Victorino on Tuesday, and the current plan is to have Jonny Gomes and a right-hander platoon in left field, but that doesn't mean they're done shopping for outfielders. Jon Morosi:
Swisher would cost Boston their second-round pick, but as Ben Cherington has said before, they're willing to do that for the right deal. After losing out on Victorino to Boston, the Indians might be willing to win this one with their wallet, though, and the Mariners, who are so desperate as to be signing Jason Bay while simultaneously thinking about trading for Jason Kubel, should be regarded as unpredictable, armed, and dangerous.
It's not a guarantee, given Swisher could slot in to left, pushing Gomes and Daniel Nava to the bench as fourth and fifth outfielders, but it's likely that acquiring Swisher would further increase the chances of moving Jacoby Ellsbury for prospects or pitching. A Gomes/Nava, Victorino, Swisher outfield wouldn't have the same upside as one with Ellsbury in it instead, but the baseline production is a lot more predictable, and it's a setup they could have in place for at least two seasons, if they so choose.
Part of the reason Victorino was more appealing than Swisher is because he can slot into center, didn't cost a draft pick, and could be had for three years. Swisher does cost a draft pick, but Boston could play the same game with him as with Victorino and Napoli, increasing the average annual value in exchange for shaving off a year from the contract. The budget might start getting a little tight once they acquire a starting pitcher, but if Ellsbury and what will likely be around $10 million in salary for him is traded, breathing room opens back up.
The draft pick part is a little harder to part with, but it shouldn't be a deal breaker for the right player. If Swisher has a few more seasons in him that resemble, oh, every season he's ever had save one in an eight-year career, then Boston will be fine sacrificing their second-round pick next summer.
That's getting a little ahead of ourselves, though, especially since, as said, the Mariners and Indians might be looking to go a little more all-out than Boston at this point after missing out on other targets.