As part of the NFL's marketing strategy in conjunction with Thursday night's season opener between the Broncos and Baltimore Ravens at Sports Authority Field at Mile High, "Kickoff" banners, many with Flacco's picture on them, have been placed throughout downtown Denver.
A large banner featuring Flacco's picture, several stories high, next to one of Peyton Manning, hangs on the stadium.
Asked on a conference call about the banner, Flacco said Sunday he completely understood the fans' ire.
"Ah, geez, yeah, I heard," Flacco said. "Somebody texted me a few nights back, when it first came out. I couldn't believe it.
"I think it's all deserved, I don't know if it's deserved towards me, I happen to be the guy they put up there. [But] I don't think here or anybody in our city would be too happy if we had somebody else from a different [team] on our stadium. I wouldn't expect anything different than all of the people in Denver to be pretty upset by it."
Manning called the banners "strange" this past week.
Some fans have organized an online petition to have the Flacco pictures and banners removed. The advertising space in downtown was purchased by the NFL from the Downtown Denver Partnership.
The Broncos, several people with the team say, resisted the idea of the Flacco banner hanging from the stadium, but the league overruled those objections.
"We appreciate the fans' passion and their desire to protect their team but think of this game as more of an opening ceremony, a celebration of the new season for the entire league," NFL vice president of corporate communications Brian McCarthy said last week. "This game will be viewed by an audience of millions and reflects the opening of the season. There will be similar banners hanging in Baltimore at the events there next week as well."