Last year was a fluke. It was fantastic, exciting and well-deserved, but it was a fluke. Replay the 2015 season 100 times, and the path that led the Broncos to a Super Bowl victory lays out once … maybe twice.

It would be dangerous for the Broncos to think otherwise.

The consensus, though, seems to be something along the lines of this: “The Broncos won the Super Bowl with a decrepit Peyton Manning and an inexperienced Brock Osweiler behind center. It doesn’t matter who’s playing quarterback, this defense will make them contenders again!”

And yeah, I agree. Last season, under those exact circumstances, I believe the Broncos could have won the Super Bowl with just about any warm body behind center, including Mark Sanchez. But change one thing — a Bradley Roby scoop-return, a dropped Steve Smith pass, a Rob Gronkowski two-point conversion, etc., etc. — and not only do the Broncos not win the Super Bowl; they likely miss the playoffs entirely.

Remember, if it weren’t for a comeback victory in overtime against the Bengals, the Broncos likely fall out of the No. 2 seed, back to the Wild Card and possibly out of the postseason; if A.J. McCarron doesn’t fumble that snap, and if DeMarcus Ware doesn’t recover that football, the Broncos don’t win, they don’t get a first-round bye, they don’t get home-field advantage and they don’t hoist the Lombardi Trophy.

The Denver Broncos deserve everything they got last season, but they’re the exception to the rule; you still need a quarterback to win in this league, and you always will.

That’s what makes this offseason so frightening.

No matter which way you splice it, there’s no get out of jail free card; a Pro Bowl quarterback isn’t walking through that door. Even if the Broncos did end up trading for Colin Kaepernick (and it would take an awful lot of creative accounting to do so), it’s no sure thing that he’s a better option than Manning/Osweiler were last season; it’s no sure thing that he’s a better option than Sanchez, for that matter. And a rookie quarterback, even Jared Goff or Carson Wentz, sure isn’t, either.

So what are the Broncos left with? Well, probably a guy like Mark Sanchez, and that’s a problem.

While Sanchez might be able to match the production that Manning/Osweiler combined for last season, there’s almost no chance that the defense (minus Malik Jackson, Danny Trevathan and David Bruton) will be as dominant as they were last year. They’ll be great, yes, maybe even historically great, but it would be unfair to expect them to bail the Broncos out for another 16 weeks. That means that the offense will have to pick up the slack, and in a big way.

Now, I’m not entirely throwing dirt on Sanchez. I think he has the opportunity to be “good,” whatever that means. But he needs help, and a lot of it. He needs a C.J. Anderson that is playing at his best all the time. He needs a Demaryius Thomas that doesn’t drop balls. He needs an offensive line that is great.

And it’s that last one that’s the most important. And it’s that last one that John Elway has devoted the most resources to accomplishing.

Behind a great offensive line, a good quarterback can go to great and a bad quarterback can go to good. That’s about the only chance the Broncos have of getting an upgrade at quarterback, and only time will tell if Elway has done enough to get it done.

The point is, though, that if the Broncos are going to win back-to-back Super Bowls, it’s going to be because the offense begins to match the production of the defense, not because the defense replicates what I believe to be the most-impactful season in NFL history by any unit, offensive or defensive.

In 2000 and 2002, two of the greatest defenses in NFL history led their teams to Super Bowl championships — the Ravens and Buccaneers, respectively. The next season, despite maintaining top-five defenses, they went a combined 17-15, because they decided to enter the year with Elvis Grbac and Brad Johnson as their quarterbacks.

Let’s just hope Mark Sanchez does not end up being the next Elvis Grbac or Brad Johnson …