ENGLEWOOD, Colo. -- If the Denver Broncos proved anything in 2017, it is how quickly optimism can turn to pessimism, and that if the offense doesn't fit the quarterback or the quarterback doesn't fit the offense, not much is going to get done.

With Denver's search for a quarterback set to move back into the public eye at next week’s NFL scouting combine, three former Broncos quarterbacks in the organization will have a lot to say about fixing things.

At the top of the football flow chart is John Elway, the Broncos’ president of football operations/general manager. Alongside him, in a more prominent role than he had last season as a senior advisor, is Gary Kubiak. Then there is offensive coordinator Bill Musgrave, who will call the plays in 2018 under head coach Vance Joseph.

Elway, Kubiak and Musgrave all played the position for the Broncos, all three in a similar variation of the West Coast offense that came from Mike Shanahan.

It's an offense that puts a premium on play-action passing, a productive run game and a quarterback who can play both in the shotgun and under center. And while Elway and Kubiak will drive the choices in both free agency and the draft at that position, it is Musgrave who will do plenty of the day-to-day work with any new arrivals.

How well Denver -- which holds the No. 5 overall pick in the 2018 NFL draft -- gets those new pieces to fit will determine the level and speed of improvement, because nothing seemed to fit through much of 2017, when the Broncos churned through three quarterbacks, fired an offensive coordinator and watched a season dissolve into a sea of turnovers and bad field position. And no matter who is under center, Joseph wants Musgrave to do more of what the Broncos tried to do after Mike McCoy was fired last November.

"As far as what I change moving forward, I think how we played offensively after we hired Billy was my vision of offense: to run the football, control the games, play great defense and to minimize the errors by the quarterback," Joseph said at season’s end. “I thought Billy did a great job of calling the game that way."

Musgrave got an up-close look at three of the best quarterback prospects when the Broncos coaches worked with the North team for a week at the Senior Bowl last month, sitting in meeting rooms with Oklahoma’s Baker Mayfield, Wyoming’s Josh Allen and Washington State’s Luke Falk.

The Broncos will get another look at the draft's top QBs -- this time including UCLA’s Josh Rosen and USC’s Sam Darnold, too -- at the combine. To that end, Elway already has spoken of the importance of not only finding a player with the skill set to play the position the way the Broncos want, but to find the player with the mental toughness to survive the mistakes that come with the job.

“Offensive football is about getting the best players we can possibly get and then putting them in the best situation to be successful," Elway has said. "We have to do a better job with that."

But as the Broncos decide about how much they’d be willing to spend on a free-agent quarterback or how early in the draft they would take one, their first priority might have to be vast improvement in how they -- and particularly Musgrave -- fit that player into what they do.

The Broncos have seen both sides of the coin; during Peyton Manning’s time, they lived the high-flying, throw-first life on offense. But in going 5-11 in 2017, the Broncos were 5-2 when they had at least 30 rushing attempts in a game and 5-0 when they had more rushing attempts than passing attempts. When Denver didn't stick to that formula, the offense struggled.

The Broncos would certainly be more efficient throwing the ball with better play at quarterback, and that would tip those scales. A rookie under center, however, would need to be protected by the run game; that, in turn, affects how the Broncos would construct a playbook.

For his part, Musgrave likes to offer things like “time on task" and “confidence from demonstrated performance" or “players first, then plays," but it’s clear a big part of the Broncos’ decisions at quarterback will be how well the plays Musgrave has on his card match the guy calling them in the huddle.