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.