The Cubs placed Carlos Zambrano on the 15-day disabled list Friday, one day after he left a start against San Francisco because of lower back soreness.
The Cubs also activated reliever Kerry Wood off the DL prior to their series opener against the White Sox. Wood had been sidelined since June 13 with a blister on his right index finger.
Zambrano won't be back until after the All-Star break. He walked off the mound after a second-inning pitch and was taken out of Chicago's extra-inning win over the Giants on Thursday.
The right-hander is 6-4 with a 4.34 earned run average in 18 starts this season.