It's tough enough replacing a starting quarterback, let alone a legend like Peyton Manning.
Yet that's the challenge facing another great QB, John Elway, who now runs the Denver Broncos team that Manning walked away from Monday.
"Peyton Manning utilized every asset that God gave him to be the best football player that he could be," Elway said. "And that, I think, to me is what sets him apart from anybody else because he got every ounce of ability that he has."
Now, whether it's Brock Osweiler, currently headed for free agency, or someone else who takes over behind center for the Broncos, Elway has an unenviable task.