He’s got power, so some team will take a shot even if it’s for a marginal minor leaguer. He’s still 5th on the team in homers and was 3rd most of the year while being platooned and basically benched after the trade deadline. Xander and JD only recently passed him in homers.
At this point, mentally he doesn’t think he can hit major league pitching. He may even figure it out, but that will not be in Boston and at age 27, his time to show anyone he can is nearly gone. As moon said, he almost certainly will not be on the 40 man next year.