Moving on from a legendary quarterback and finding his replacement without skipping a beat is one of the toughest tasks for any GM. In the last eight years, it has been done twice, with the Packers' transitioning from Brett Favre to Aaron Rodgers and then the Colts' transitioning from Peyton Manning to Andrew Luck. Before that however, it had been done only once in the history of the NFL when the 49ers transitioned from Joe Montana to Steve Young. 

Many other teams with legendary quarterbacks failed to replace them with another franchise signal caller. This includes the Dolphins' moving from Dan Marino to Jay Fiedler, the Steelers' moving from Terry Bradshaw to Mark Malone, the Cowboys' moving from Troy Aikman to Quincy Carter, the Broncos' moving from John Elway to Brian Griese, and the list goes on. 

The Broncos looked like they were in perfect position to transition from Peyton Manning to Brock Osweiler. When Manning got hurt in week 10 vs Kansas City, Osweiler took over in the fourth quarter and then started every game for the rest of the regular season. Osweiler looked like he was a clear upgrade over Manning: 

Now, I know that Osweiler is no Young or Luck, but he had the advantage in pretty much every statistical category over Manning, and it looked like he was going to be Denver's starting quarterback heading into the playoffs. However, in the final regular season game against San Diego, the offense struggled in the first half under Osweiler, and he was benched for Manning. Manning was able to give the Broncos a spark and help Denver secure a win. 

This spark led the Broncos to choose Manning as the starting quarterback for their playoff run, but this was a bad decision. This move sent a message to Brock Osweiler that the Broncos didn't believe in him, even though he was clearly a better quarterback than Peyton Manning at the time. Osweiler clearly held a grudge against the Broncos for this decision as evidenced by this tweet from Mike Klis of the Denver Post:

Broncos figured Brock Osweiler didn't want to come back when he stopped returning phone calls to coaches/some teammates past 2 weeks. #9news

— Mike Klis (@MikeKlis) March 9, 2016

Osweiler ended up signing a deal with Houston that will pay him $18 million per year with $37 million guaranteed, while Denver was in the range of offering $16 million per year with $30 million guaranteed. This was terribly mismanaged by Denver. The Broncos had the heir apparent to Peyton Manning lined up and already playing well in their system. Instead of handing over the reins, they damaged the relationship between themselves and Osweiler, and now he's gone. 

The contrary argument is that Denver ended up winning the Super Bowl with Manning at quarterback, so was it really a bad decision? And to that I would say yes, it absolutely was, for all the aforementioned reasons about Osweiler and because Manning did nothing in the playoffs. In three  games, Manning put up a bad stat line: 180 yards passing per game, 55.4% completion, two touchdowns, one interception, and a passer rating of 75.4. Manning did very little aside from riding the coattails of his dominant defense, something Brock Osweiler could have easily done just as well or probably better. 

So with their young, promising quarterback of the future now in Houston, the Broncos have traded for former Jets and Eagles quarterback Mark Sanchez. Sanchez is primarily known for being part of one of the most embarrassing plays in NFL history: the "butt fumble" against the Patriots on Thanksgiving four years ago. 

Sanchez is already 29 years old, and he has a career 56.7% completion rating, 86 touchdowns, 84 interceptions, and a passer rating of 74.3. Statistically he is a bad quarterback, and it's not likely he will get any better in eighth year in the league. Now without Osweiler, the Broncos look like they are in no-man's land at quarterback, with an uninspiring Sanchez filling in for now. 

The only promising option the Broncos could possibly have is chasing Andrew Luck in next year's free agent class. Sanchez is currently on a one-year deal, so his money will be coming off the books next year, giving the Broncos another opportunity to look for a franchise quarterback. The Colts have done a very bad job surrounding Luck with talent since they drafted him, and if things go badly for them next year, Luck could look to test the market in free agency. Denver would absolutely look to sign Luck if those circumstances came about.  

If those plans don't work out, though, and the Broncos are stuck with Sanchez or looking desperately for another quarterback, this will make John Elway and company look foolish. The Broncos had their next quarterback already in their organization, in a prime position to keep him, to make a smooth transition from Manning to the future, and they blew it. This is something that may really hurt Denver for time to come, because history shows us that it is very hard to transition from a great quarterback directly to another good one. While Osweiler was still unproven, he certainly displayed a solid skillset that and a winning mentalitiy. And with that unfavorable history, we have no idea when or where Denver will have the chance to get a good quarterback again.