Boston acquired Minor League right-hander Dan Turpen in the trade.
Ramirez, a righty, was inconsistent for Boston this season, going 0-3 with a 4.46 ERA.
He pitched in 44 games this season, walking 16 and striking out 31 over 42 1/3 innings. The Red Sox acquired Ramirez from the Royals for Coco Crisp in November 2008.
Ramirez was as solid for the Red Sox in '09 (2.84 ERA in 70 games) as he was for the Royals in '08 (2.64 ERA).
In his career, Ramirez is 16-14 with a 3.55 ERA in 268 appearances, all out of the bullpen.
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.