DENVER —The Chicago Cubs have placed right-hander Carlos Zambrano on the 15-day disabled list a day after he was scratched from his start with muscle spasms in his back.

The team recalled righty Jeff Stevens from Triple-A Iowa on Saturday.

It's Zambrano's second trip to the disabled list this season. He was out in May with a left hamstring strain. The move Saturday is retroactive to Aug. 2.

Zambrano (7-4) was scheduled to pitch against Colorado on Friday night, but was scratched 15 minutes before the game.

He went three innings in his last start against Florida on Aug. 1, before departing with lower back stiffness.

Stevens is with the Cubs for a third time this season. In five relief appearances he has a 2.84 ERA.