Possible Suitors for Jacoby Ellsbury:
The Rangers farm system is full of good prospects. My guess is star in the making Jurickson Profar isn't on the table, but with Sox top prospect Xander Bogaerts a year or two away from MLB action, the Sox can do without Profar. 3B Mike Olt is a possibility, but unlikely as the Red Sox have a good young third baseman in Will Middlebrooks. My guess is the Red Sox will ask for top-pitching prospects. Most likely they will demand Rangers young lefty Martin Perez. Perez is the Rangers top-pitching prospect, but if they don't intend to resign Josh Hamilton and would rather spend that money on Ellsbury, giving up Perez looks like a reasonable investment for the Rangers who have a number of good starting pitchers other than the unproven Perez.
The St. Louis Cardinals have Carlos Beltran and Matt Holliday in the corner outfield spots, but Ellsbury would be a big upgrade over current center fielder Jon Jay. Shelby Miller, the Cardinals top prospect, is Major League ready, and while the Cards don't want to part with him, Chris Carpenter, Adam Wainwright, and Jaime Garcia make up a favorable rotation before they even add Shelby Miller into the mix. Also, the Cardinals have 2 other young pitching prospects with lots of potential in Tyrell Jenkins and Carlos Martinez each one more season closer to joining the big league squad. If I were the Red Sox I would hope the Cardinals would make it known they were looking to trade for Ellsbury because they have prospects the Red Sox covet.
The Braves have a number of pitching prospects including Julio Tehran and Randall Delgado. My guess is one of these pitchers combined with RHP Zeke Spruill would be what the Red Sox look for here. With Michael Bourn most likely leaving for free agency, the Braves are looking for a replacement center fielder, but may not have the money to sign him to an extension. Should they not sign him to an extension, the Braves would be giving up quite a haul to the Sox for one year of Ellsbury, so my guess is they will only make a trade for him if they know they can/will sign him to an extension.
The Giants most likely do not have the requisite pitching prospects to trade the Red Sox in return for Ellsbury. They will not want to trade prized prospect Gary Brown, and without Brown or any MLB ready pitching prospects in the mix, the Giants should count themselves out of this, unless they do something tricky.
The Rays are an interesting team. The Rays have a wealth of great prospects, especially pitchers. They have a need for a center fielder, with B.J. Upton most likely leaving for free agency, but unlike the Cardinals or Rangers, the Rays do not have the money to pay Ellsbury past the 2013 season. Were the Rays to offer Chris Archer or Alex Cobb to the Red Sox in exchange for Ellsbury, I would pull the trigger on that deal every day of the week were I making the decisions in the Red Sox front office.
My impression: Were any of these teams, other than the Giants, to make a solid offer to the Red Sox, I would do it. The best team to negotiate with has got to be the Tampa Bay Rays because they have the greatest wealth of young pitching, but they are historically stingy about giving up prospects, thus don't count on them giving up too much for only one season of Ellsbury. The best bet overall has to the Cardinals, who have Shelby Miller and other younger prospects to trade and with Ellsbury in center field would have the best outfield in the Major Leagues. John Mozeliak, pick up the phone.