"The Cubs placed Carlos Zambrano on the 15-day disabled list with a back injury before Friday's game against the White Sox.

Zambrano was unavailable for comment after being examined by a team physician Friday morning. He was also on the DL with back soreness in 2009.

Kerry Wood was officially activated, and will take Zambrano's roster spot. Zambrano was only expected to make two more starts before the All-Star break."