A developing story from the Boston Globe: Boston Police and medics were called to John Henry's yacht, Iroquois, to tend to a man who died. Efforts were made to revive the man, said to be 28-30-years old, but were unsuccessful.
So far the Globe story indicates that the likely cause of death was suicide, and that the man may have been working on the boat. No name is given at this time.
A BPD spokesperson said the Red Sox were likely to issue a statement, although I doubt it will have any more than you'll hear out of the police.