Feliz joined the Tigers Saturday at Minnesota, a week after being let go by the Texas Rangers.
Feliz entered this season with a 2.53 career ERA, but he lost his job as the closer after blowing three of nine save opportunities. Feliz had 72 saves over the 2010-11 seasons, helping the Rangers reach the World Series both years.
The Tigers have the sixth-worst relief ERA in the majors at 4.04, entering their game against the Twins. Manager Brad Ausmus said closer Joakim Soria is currently the only one in the bullpen whose role is secure.
Feliz replaced rookie right-hander Jeff Ferrell, who was optioned to Triple-A Toledo.