Kensing hasn't pitched in the Majors since 2009, when he was with Washington. The 29-year-old made 26 appearances out of the Nationals' bullpen that year. He posted an 8.68 ERA, walked 12 and struck out 12 in 28 innings.
Kensing missed the entire 2010 season recovering from elbow surgery and began last season pitching in independent ball. The Yankees signed him to a Minor League deal in late June, and Kensing spent the rest of the year playing on New York's Triple-A club in Scranton Wilkes-Barre. In 21 appearances there, Kensing had a 4.28 ERA.
A former second-round Draft pick, Kensing began his career with the Marlins. He pitched in Florida for parts of six seasons before being traded to the Nationals in April 2009. Kensing has a career 8-9 record and 5.81 ERA in 134 Major League games.
The signing brings the Pirates' list of non-roster Spring Training invitees to 11. Kensing is one of five pitchers in that group, which also includes Tim Wood, Jo-Jo Reyes, Shairon Martis and Ryota Igarashi.