Big Z goes to DL

The Cubs placed starting pitcher Carlos Zambrano on the 15-day disabled list Saturday with muscle spasms in his back.

Zambrano was scratched from his scheduled start at Colorado on Friday. This marks the second trip to the disabled list for the team's right-handed ace, who was shelved from May 4-22 because of a strained left hamstring.

The Cubs recalled right-handed relief pitcher Jeff Stevens from Triple-A Iowa to replace Zambrano on the roster. Stevens, 25, is 0-0 with a 2.84 ERA in five appearances for the Cubs this season.

Left-handed pitcher Sean Marshall emerged from the bullpen to start in Zambrano's place Friday. The Cubs did not say whether Marshall would maintain Zambrano's spot or whether another pitcher would fill Zambrano's turn in the rotation next week.

Zambrano, 28, is 7-4 with a 3.35 ERA in 20 starts this season.

-Tom Musick