The Broncos, Tennessee Titans, and the San Francisco 49ers were all trying to get Manning after he was released from the Indianapolis Colts nearly two weeks ago.
A source said Monday that Manning told his agent to complete a deal with the Broncos. Once the deal is official, Denver will try to trade Tim Tebow, who led the Broncos to the playoffs last season.
According to ESPN, Broncos vice president of football operations John Elway and Manning first discussed the parameters of a five-year, $95 million contract during their March 9 meeting. It was the first time that Manning visited a team during his free agency.
Manning missed all of last season because of several neck surgeries, but the Broncos apparently have few concerns with his medical condition. Sources say Manning has already passed a physical exam administered by a team of Broncos doctors.
Manning's move to Denver would allow him to stay in the AFC, a conference he knows well and one considered weaker than the NFC at the moment, and potentially re-establishes the tantalizing prospect of playing against his brother, New York Giants quarterback Eli, in a Super Bowl.
ESPN and The Associated Press contributed to this story.