The Cubs have activated reliever Carlos Marmol from the 15-day disabled list and optioned Rafael Dolis to Triple-A Iowa.
Manager Dale Sveum says Marmol will be used in a setup role and not as the closer, a job he lost to Dolis this month.
Marmol then went on the DL because of a strained right hamstring on May 12.
He was 0-1 with a 6.35 ERA in 15 appearances this season and had two blown saves in four chances before Monday's game against San Diego.
Dolis wasn't much better with a 2-4 record, 5.68 ERA and four saves in six chances.