The Chicago White Sox say they have acquired right-handed pitcher Zach Stewart off waivers from the Pittsburgh Pirates.
Stewart was 1-4 with an 8.58 ERA in 20 games last season for the White Sox and Boston. He was traded to the Red Sox with infielder Brent Lillibridge on June 24 in exchange for third baseman Kevin Youkilis. He was traded to Pittsburgh in November and designated for assignment Jan. 17.
Stewart originally was acquired by the White Sox from Toronto on in 2011 with pitcher Jason Frasor in exchange for pitcher Edwin Jackson and infielder Mark Teahen.