The 38-year-old, whose Broncos (2-1) are on their bye week after an overtime loss in Seattle, appeared to have a contemplative moment inside the Volunteers' locker room before the game.
Manning threw for a school record 11,201 yards and 89 touchdowns in four seasons at Tennessee and was the runner-up for the 1997 Heisman Trophy (to Michigan's Charles Woodson).
Manning didn't bring his alma mater good luck, however, as the Vols fell 2-2 with a 38-35 loss to the Bulldogs. They have now lost five of their last six SEC games dating back to last season.
- Chris Mascaro