The Pirates have announced that they claimed left-hander Aaron Thompson off waivers from the Nationals. Thompson, 23, is a former first-round pick of the Marlins and went 5-13 with a 5.65 ERA in 2010, almost all at Double-A.
To make room on the 40-man roster for Thompson, the Pirates designated left-hander Will Ledezma for assignment. Ledezma went 0-3 with a 6.86 ERA in 27 relief appearances last season for Pittsburgh, his sixth team in four years.
The Pirates also announced they signed infielder Garrett Atkins to a minor-league deal with an invitation to major-league spring training.
-- David Andriesen