All three quarterbacks were draft picks by Elway, the Hall of Fame quarterback who has only had success at quarterback in free agency.
The 30-year-old Keenum is considered the second-best QB available on the open market. One of those making the rounds Monday morning comes from NFL Network's Tom Pelissero, who mentioned the Buffalo Bills as a "team to watch" when it comes to Vikings quarterback Sam Bradford.
He missed most of the 2017 season with a knee injury.
Case Keenum #7 passes the ball to Adam Thielen #19 of the Minnesota Vikings in the second quarter of the game against the Chicago Bears on December 31, 2017 at U.S. Bank Stadium in Minneapolis, Minnesota.
Keenum was particularly brilliant in the second half of the season, when he threw for 15 touchdowns against four picks while leading the Vikings to a 7-1 record.
Keenum has ties to former Broncos quarterback and current senior personnel advisor Gary Kubiak having played for Kubiak when he was the head coach of the Texans. "Obviously, we have to get better at that (quarterback) position".
Only the winless Cleveland Browns threw more interceptions than the Broncos' 22, and Denver had just one receiver catch more than 50 passes and finish with more than 560 yards receiving - Demaryius Thomas with 83 catches and 949 yards.
With the start of free agency just two days away, reports of interest among teams and players will be frequent.
At the National Football League scouting combine this month, Elway said, "we'll continue to look at all of the options out there when it comes to quarterback". "That was always fluid, too, but he was our target".
The Vikings went 11-3 in games started by Keenum during the regular season on their way to a first-round playoff bye. Their inconsistent play on both the offensive line and at quarterback have been big reasons why they've sat out the postseason. We didn't play well there a year ago. There were some things that we should have done, that we should have done differently that we didn't do.