When it comes to evaluating quarterbacks in the NFL draft, Denver Broncos executive vice president of football operations/general manager John Elway has a rather unique perspective, even among his peers of NFL decision-makers.

When he evaluates quarterbacks, in particular, in each NFL draft, he does it having been a former No. 1 pick in the 1983 draft who went on to a Hall of Fame career at the position.

And as Elway looks at the current state of quarterbacks in college football, including the group on this year's draft board that includes Jameis Winston and Marcus Mariota, he sees a significant learning curve for the passers who have spent their careers in spread offenses.

"It makes it more difficult, there is no question," Elway said in recent days. "Mariota is in the same situation, the fact that he hasn't been under center very much, but I think there hasn't been a lot of success with guys that have been in a shotgun offense all the time that has had a lot of success. I think (Carolina Panthers quarterback) Cam (Newton) is one guy you can point to that has had success doing that. There have been a lot more guys that haven't made the transition than have made the transition. It's always tough. I think it is part of the projection that you to make these days."

Mariota played in Oregon's spread attack and said at the scouting combine this past February that is pre-draft work had included working in a huddle for the first time -- Oregon didn't use one -- and calling plays since the Ducks coaches simply had signaled plays in from the sideline.

Winston didn't play in a pure spread offense and is considered to be the more pro ready of the top two passers, but he did line up in the shotgun plenty. Elway said most teams still put the quarterback under center at times because even that basic adjustment would take some time for many in the newest crop of rookie passers.

"When I look at that transition, the biggest thing is probably being able to see because one thing shotgun does do is allow you to see better," Elway said. "If you haven't been under center, there is an adjustment to being able to come out and you're more limited to what you can see because the big guys are right in front of you. I think that is the biggest adjustment that they have to make."

It's why Elway said a quarterback like Colorado State's Garrett Grayson, who played under center plenty in his career for the Rams, could have a slight advantage in his draft evaluation because, as Elway put it, "he's probably more ready."

Overall, in Elway's tenure as the Broncos' chief football decision-maker, the Broncos have taken quarterbacks twice in the previous four drafts. The Broncos selected Brock Osweiler in the second round of the 2012 draft, the year they signed Peyton Manning in free agency, and they selected Zac Dysert in the seventh round of the 2013 draft.

Osweiler has been Manning's back-up for the last three seasons and Dysert spent the 2014 season on the practice squad after being the team's No. 3 quarterback in '13. Elway said while the Broncos have Manning back for the '15 season and Manning is under contract for 2016 as well, the Broncos would grab another passer if the right one presented himself as the picks unfold later this week.

"We are wide open to everything," Elway said. "We never really lock into anything. I think that as much as we go in with a plan, that plan always changes because of the different things that go on during the draft. What we try to do is cover all situations. We are really trying to find football players that are going to make our football team and make us better regardless of what the position is."