Who knows why the Sox did it, but they traded for former Red Sox Kason Gabbard:
The Rangers have traded left-hander Kason Gabbard to Boston, the team who traded him for Eric Gagne in 2007, for cash considerations. The Red Sox have assigned him to Triple-A Pawtucket and are expected to send him to extending spring training. Gabbard, who was made a reliever this season, had struggled at Triple-A Oklahoma City. In his last appearance Tuesday, the left-hander allowed six runs in one inning.
I'm not sure why we need him, but sure. He's on the team. I wouldn't expect to see him with the big club any time soon...