To clear up room for Balfour on the 40-man roster, the Reds designated right-hander Josh Hancock for assignment. The club has 10 days to trade, release or outright Hancock to the Minors.
In other news, the club signed infielder Frank Menechino and catchers Steve Torrealba and Ryan Hanigan to Minor League contracts with invites to Spring Training camp and named Gene Kerns a professional scout.
At the end of last season, doctors predicted Balfour won't be at full strength until this May, because he suffered setbacks during his rehabilitation. This past fall, Balfour had another surgery to repair a torn rotator cuff and torn labrum.
In his career, which began with Minnesota in 2001, Balfour has typically been used as a middle reliever. He's compiled a career record of 5-1 with a 4.63 ERA in 55 appearances, including one start, over the course of the '01, '03 and '04 seasons.
The Twins did not tender a contract to Balfour last month, and the Reds swooped him up.
Balfour, who recently turned 28, showed signs of strong command at times during the 2004 season, during which he went 4-1 with a 4.35 ERA in 36 relief appearances.
Anthony Castrovince is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.