Keenum is moving on from Minnesota. He will sign with the Broncos when free agency opens Wednesday, Adam Schefter of ESPN reported early Tuesday.
Cousins apparently has three serious suitors remaining in the Jets, Cardinals and Vikings, with the Broncos having found what they hope is the long-term solution at the position.
Keenum, 30, had a career year in leading the Vikings to the NFC Championship Game after replacing the injured Sam Bradford. He threw for 3,547 yards with 22 touchdowns and seven interceptions during the regular season.
Keenum will play for his third team in three years, hoping he has found a home in Denver.