Who's the biggest question mark for the Broncos heading into this NFL season?
It's Peyton Manning.
Yes, I know it sounds like heresy to utter any doubt about one of the greatest quarterbacks in league history.
Since 1998, when Manning turned pro, he has thrown the football nearly 40 miles, been named the league's most valuable player five times and won a Super Bowl ring. But has an NFL offense with Manning at the controls been more of a mystery than the Broncos are in 2015?
In years past, Denver receiver Demaryius Thomas insists, Manning hasn't always looked sharp during the preseason, yet the Broncos were fully capable of scoring 35 or 42 points when the games began counting in the standings.
So can we mark down the Broncos for five or six touchdowns against the Ravens?