Case Keenum was 1-for-4.
Two months after leading the Vikings to the NFC championship, Keenum signed a two-year, $36 million deal in Denver, and the Broncos traded Trevor Siemian to the Vikings to serve as Cousins' backup - so long as he beats out another former Denver QB Kyle Sloter.
Keenum wasn't the only Broncos quarterback whose performance was lacking against the Vikings.
Lynch, the former first-rounder twice beaten out by Siemian in Denver, was just 6 of 11 for 24 yards and an interception.
The Broncos were outgained 269-61 in the first half of a loss to the Vikings on Saturday night.
Chad Kelly came on and played much better, throwing for 177 yards, two touchdowns and an interception on 14-for-21 accuracy, drawing a rave review from the crowd. His strike to Jeff Badet for the 2-point conversion made it 35-28. Sloter also ran 14 yards for a score with about three minutes left in the game.
Sloter completed 9 of 11 passes, including a 9-yard strike to wide receiver Chad Beebe in the fourth quarter. Last year, Joseph stuck with McKenzie despite half a dozen fumbles.
For the first time in 223 days, the Denver Broncos took the field at Broncos Stadium at Mile High for an actual game on Saturday night.
Here are the five biggest takeaways from the matchup against the Minnesota Vikings.
Marshall and Thomas emerged from the tunnel behind the Broncos' bench after the anthem was over.
Broncos S Jamal Carter (hamstring), CB Marcus Rios (hip) and TE Austin Traylor (right shoulder) got hurt.
Vikings: Host Jaguars on August 18.