CHICAGO (Ticker) -- The Chicago Cubs activated reliever Rick Aguilera from the disabled list prior to today's doubleheader and outrighted lefthander Dan Serafini to Triple A Iowa of the Pacific Coast League. Aguilera has been sidelined since August 1 with a strained left calf. The Cubs acquired the 37-year-old Aguilera from the Minnesota Twins on May 21, shortly after closer Rod Beck was sidelined with an elbow injury. Aguilera was 3-1 with six saves and a 1.27 ERA in 17 games for the Twins. However, Aguilera has struggled with the Cubs. In 28 appearances, he is 4-3 with four saves in eight opportunities and a 5.72 ERA. Aguilera has allowed 33 hits -- including six homers -- in just 28 1/3 innings with Chicago. Aguilera ranks 13th with 285 career saves. Serafini was 3-2 with one save and a 6.93 ERA in 42 games for the Cubs. He has allowed 86 hits in just 62 1/3 innings.