What would it take to trade for him?
He is a FA after 2013. He is likely to make about $10MM in arbitration this year. He is also coming off of an injury plagued down year. The Red Sox don't seem primed to contend in 2013 although they are an organization that looks to contend every year.
They seem to have a hole at 1B and LF. In addition their SP is aging quickly.
I wonder if something like Tony Cingrani (or Corcino if they prefer), Donald Lutz, and Drew Stubbs would work? My guess is they'd demand Frazier, which I probably wouldn't do.
Ellsbury would be a perfect fit for the 2013 Reds. He bats LH, is a great leadoff hitter who could keep things warm for Billy Hamilton in 2014. Worst case if Hamilton is forcing his way to Cincy, we could move Ellsbury to LF for the second half of the season, or trade him at the deadline if we were out of contention.
Otherwise, give him a qualifying offer next offseason, thank him, and collect the draft pick when he signs elsewhere. Coming back to the original question, what would it take to pry him from Boston?