"As previously stated on Monday, Sept. 5th, Peyton Manning has undergone further testing and consultation with several specialists regarding his rehabilitation. The results of these tests and the consensus of the consultations was that further surgery was warranted. Peyton has undergone this surgery today by having a single level anterior fusion. The surgery was un-eventful," the team said in a statement.
Although Manning will remain on the active roster, the Colts have not set a timetable for his return.
Manning has started every game for the Colts since 1998. His absence means Kerry Collins will step in to start against the Houston Texans on Sunday. Collins, who had announced his retirement on July 7, was signed by the Colts last month as insurance in case Manning wasn't ready.