The team signed him to a minor league contract on Wednesday, four days after he was released by the Florida Marlins.
Helms, a 13-year veteran, has struggled this year, batting just .191 with six runs batted in through 69 games for the Marlins.
The 35-year-old Helms was drafted by the Braves in the 10th round in 1994 and broke into the majors in 1998. He was traded following the 2002 season to Milwaukee. Helms, who has also played for the Phillies, is a career .256 hitter with 75 homers and 374 RBI in 1,212 games.