It was only two seasons ago that the Broncos finished 9-7. And the season before that, Peyton Manning's last, they won a Super Bowl. But other than Manning, who didn't play particularly well during that final campaign, general manager John Elway hasn't had much success in finding that next great franchise quarterback.

After going 5-11 in 2017, the Broncos moved on from Paxton Lynch, Brock Osweiler and Trevor Siemian, and signed Case Keenum to a two-year, $36 million deal. Keenum was coming off a career year in Minnesota where he completed 67.6 percent of his passes for 3,547 yards with 22 touchdowns and just seven interceptions. He helped the Vikings to the NFC Championship Game, and was a legit MVP candidate.

But Keenum hasn't been able to replicate that success in Denver, at least through the first half of the season. The Broncos are 3-5 and he's completing just 63.9 percent of his throws with 10 touchdowns and 10 interceptions. He's also been sacked 22 times -- the same number he endured for the entirety of 2017.

There's more: Keenum ranks 23rd in value per play among all quarterbacks, according to Football Outsiders, which is just ahead of Blake Bortles, Eli Manning and Jameis Winston. A season ago he ranked first.

"Case will be the first one to tell you that some of the decisions haven't been really good," Elway said this week, via's Jeff Legwold. "He works on that. I know that he's not trying to do it and he continues to work on that and try to prevent the turnovers. ... We also have to get him in good situations too."

For Keenum, measuring success is simple.

"I grade myself on wins and losses, so, we're 3-5," he said. "That's how I grade myself. We've done some things, we've won some games, but we've left a lot on the table. I think offensively we've done some things, to move the ball, scored some points, won some games and made some big plays at times, but not enough of those things. We have to do better going forward."

Here's the good news: On a play-by-play basis when compared to the other 31 teams, the Broncos haven't been bad. In fact, they've been quite good; FO ranks them seventh overall (10th on offense, seventh on defense). The reason: Through the first eight games only the Raiders played a tougher schedule than the Broncos. But there shouldn't be any excuses over the next eight games: Denver's schedule ranks 17th, which goes some way in explaining how a 3-5 team currently in third place in their division still has a 16.2 percent chance to eke out a wild-card spot.

Ultimately, any success the Broncos have over the next two months will start with Keenum playing more like he did a season ago in Minnesota and not like the replacement-level passers that preceded him in Denver.