(CBS News) -- Indianapolis Colts quarterback Peyton Manning will likely be out for the remainder of the season, team owner Jim Irsay announced at breakfast meeting with Super Bowl donors Monday, saying that Manning may take practice snaps in December, CBS News affiliate WISH-TV in Indianapolis reports.

The announcement comes after the Colts turned to their third string quarterback in a 23-20 loss to the Pittsburgh Steelers.

Sources at the breakfast meeting told WISH-TV that Manning won't practice again until December and may not play again until 2012.

Irsay later clarified via Twitter that a Manning-less season was not "for sure" and that the team is keeping him on the active roster.

There is an outside chance, Irsay posted, that Manning could return in December.

The Colts confirmed Sept. 8 that Manning had a "single-level anterior fusion" and that the surgery was "uneventful."

Peyton Manning has 3rd surgery, return in doubt

The procedure was the outcome of tests and consultations after his recovery from a previous neck surgery in May was progressing slowly. The surgery in May was to repair a bulging disc.