The Pirates announced the trade Tuesday.
Worley was acquired in a trade that sent outfielder Ben Revere to the Philadelphia Phillies before last season and he was the starter on Opening Day for the Twins. But he went 1-5 with a 7.21 ERA in 10 starts for the Twins and spent most of last season at Triple-A-Rochester.
He came to spring training a long shot to make the Twins' revamped rotation, but posted a 13.50 ERA in 10 2/3 innings before being placed on waivers last week. Worley cleared waivers and was outrighted to Rochester on Friday.