ATLANTA -- Chicago left-hander Ted Lilly has delayed his rehabilitation start for Triple-A Iowa because of a stiff back.
Lilly is on the 15-day disabled list to open the season as he recovers from shoulder surgery. He was scheduled to start for Iowa on Friday but instead has been rescheduled to start on Sunday.
Cubs manager Lou Piniella says Lilly's stiff back "is not a setback."
Lilly hoped to be ready for the start of the season before he missed about a week of spring training with a fever of 103 degrees and flulike symptoms.
Lilly was the Cubs' only All-Star last season when he was 12-9 with a career-best 3.10 ERA.
Lilly started experiencing back spasms while throwing on the side on Tuesday, a team source told ESPNChicago.com's Bruce Levine.
Lilly has returned to Chicago to undergo physical therapy from Cubs personnel before heading to Iowa for his start on Sunday.
Information from The Associated Press and ESPNChicago.com's Bruce Levine was used in this report.