Balfour's deal is a two-year deal worth $12 million, according to Jeff Passan of Yahoo Sports.
Balfour, 36, went 1-3 with a 2.59 ERA and a 1.197 WHIP in 65 games with the Oakland Athletics in 2013. His 38 saves ranked sixth in the American League. He had a 145 ERA+. Over his career, Balfour has a 128 ERA+ with 72 saves.
The Rays pulled off a good deal with Balfour. Their bullpen posted the 12th-worst ERA in the Majors in 2013 with a 3.59 mark. Balfour could help bolster the back end of the staff at a cheap rate.