It’s always good to have a backup plan, especially when it comes to free agency. For several teams this offseason, Kirk Cousins is Plan A. The 29-year-old is set to officially become a free agent next week, and a number of teams are expected to kick the tires on the veteran quarterback. In the case of the Broncos, Case Keenum reportedly is Denver’s Plan B if the team is unable to reel in Cousins. Keenum also is primed to become a free agent when the new league year opens after not receiving the franchise tag from the Minnesota Vikings. And the Vikings, who reportedly also are in on the Cousins sweepstakes, appear to have their backup plan lined up as well.