Romney also issued a statement Monday thanking the two-time Super Bowl champion for his endorsement. 

“Leaders come in many forms, and John Elway has always exemplified leadership, first as a quarterback for the Super Bowl champion Broncos, and now as an executive vice president for the team,” said Romney. “He’s had to overcome challenges during his career, and he knows what it takes to turn things around when things get tough. I’m proud to have him on my team as we campaign to lead the comeback this nation desperately needs.”

Elway appeared later Monday at a rally for Romney in Denver, where the campaign reported 5,500 in attendance. Elway quickly introduced Romney, and referenced the Broncos' 37-6 win Sunday over the Oakland Raiders.

"I must say today has been a very good day. Not only because of what happened yesterday but because I get the opportunity to introduce to you the next president of the United States, Mitt Romney," Elway said.

One of the crowd in attendance was Colorado Rockies' all-star first baseman Todd Helton, who also apparently endorsed Romney. At the event, Romney said he was "honored" to be introduced by Elway, and called the quarterback an "extraordinary man."

Of Colorado, Romney said the state was "home to a pretty darn good football team."

"And one more thing, I think this is going to be home to the place that elects the next president of the United States," he added to loud cheers.

Romney also referenced the looming debates, saying he wasn't interested in questions of who would win or lose or land the most punches.

"In my view its not so much winning and losing, or even the people themselves, it's about something bigger than that. It's about describing the pathways forward," Romney said.

The Romney campaign hopes his debate performance — and the support of two of the state's highest profile athletes — can help provide a bump in Colorado. A WeAskAmerica poll released last week gave President Obama a 49-46 percent lead in the state.

This post was updated at 9:43 p.m.