OAKLAND -- The A's on Friday acquired right-handed reliever Chris Resop from the Pirates, to whom they dealt Minor League righty Zach Thornton in a trade.
To clear a spot on the 40-man roster for Resop, the A's designated righty Sandy Rosario -- acquired Wednesday from the Red Sox -- for assignment.
Resop, 30, was 1-4 with a 3.91 ERA in 61 relief appearances with Pittsburgh last season, tossing a career-high 73 2/3 innings along the way -- good for seventh among National League relievers.
Resop has a 4.51 career ERA with two saves in 213 relief outings spanning parts of seven seasons with the Marlins, Angels, Braves and Pirates.
Thornton, a 23rd round Draft pick by the A's in the 2010 First-Year Player Draft, spent the 2012 campaign at Class A Stockton, where he was 4-0 with 16 saves and a 4.53 ERA in 48 appearances.