The Oakland Athletics have acquired right-hander Sandy Rosario from the Boston Red Sox for a player to be named later or cash considerations.
The AL West champion A's cleared room on the 40-man roster by designating outfielder Jermaine Mitchell for assignment.
Boston claimed Rosario off waivers from Miami on Oct. 17 after he spent the year in the Marlins organization. He began the season with a 1.04 ERA in 25 outings at Triple-A New Orleans while converting all 16 of his save opportunities. The 27-year-old right-hander joined the Marlins on June 8, posting an 18.00 ERA in four relief appearances before going on the disabled list June 16 with a strained right quadriceps. He wasn't back in the majors after that.
Earlier Wednesday, the Red Sox sent infielder Danny Valencia to the Baltimore Orioles for cash.