ESPN analyst Bill Polian knows that the best way to attack the draft is without a glaring need at a key position. Teams that enjoy that luxury -- including the Broncos, who have an experienced starting option at every spot in the lineup -- have the freedom to not be locked into a specific position, which leads to reaches.

"If you have those cornerstone positions and you're comfortable with the guys you have there, and you have them under contract, it gives you the ability to go into the draft and take the best player that pops up on the board for you," said the former team executive and member of the 2015 Pro Football Hall of Fame on a conference call Tuesday.

One year in which Polian did not have that flexibility was 1998, his first as president of the Indianapolis Colts. They held the No. 1 overall pick and needed a quarterback in the worst way, but had their choice of two premium prospects: Peyton Manning and Ryan Leaf.

What seems clear-cut in retrospect was murky at the time to some observers and executives -- but not to Polian, who said he and the Colts reached the decision to pick Manning in early April 1998, after conducting workouts with both quarterbacks.

"We had done extensive work on every facet of their football lives up until then," Polian said. "There was a wide gap, and it was really a combination of playing ability, processing ability and work ethic and maturity.

"So that was a relatively easy decision after we'd done all the work."

ON TO THE 2015 DRAFT:

Polian does not expect either of the top two quarterbacks -- Florida State's Jameis Winston and Oregon's Marcus Mariota -- to linger on the board. If Winston goes to the Buccaneers with the top pick, he believes Mariota will be off the board with two selections.

"If you want to be sure to get him, you've got to go to two and three," Polian said. "There's at least a lot of talk that people will try to [trade] up and get him. It would seem to me that the likelihood of his being there (at the No. 6 pick) is not great."

But neither will be ready to succeed immediately, and both can expect to endure some early bumps, Polian added.

"Mariota and Winston are both rookie quarterbacks, and rookie quarterbacks need time to develop. They do not come in ready-made and tailor-made to play," Polian said. "Andrew (Luck) is an outlier. Peyton (Manning) struggled for the first two-thirds of his rookie year. RGIII came into a situation where they built the offense around his skill set, and he did fine until he got hurt, but that was a bit of an outlier as well.

"I think both guys are going to be projects that you're going to have to work with. That's the case with all rookie quarterbacks, and I think that's the case here. They're going to make mistakes. The game's going to speed up for them. All of the things that we hear every year -- at this time of year, all we hear is how great they are and how good they're going to be, and six months from now, we'll hear about how big a jump it is to this level and how hard it is to get used to the speed of the game, etc., etc. That's just the way of the world and the way of the NFL."

But little separates the quarterbacks from the rest of the field in terms of talent; what places them at the top of the class -- and potentially 1-2 in the first round -- is the premium placed on their position.

"This is a strange draft. You've got a lot of players -- even including the two quarterbacks at the top in the first round -- that are kind of bunched together," Polian said. "There's not a lot of separation -- at least in my mind -- between these players.

"So that would lead you to believe that absent the quarterback position, there would not be a lot of (trade) movement."

But Polian believes there could be some trades late in the first round.

"Because there are not 32 first-round players in any given draft -- that's always a fact -- in the lower third (of the first round), you always see a lot of movement, because people want to get out and pick up extra picks because they feel they're getting the same player at 41 that they would get at 26," Polian said.

"That's normal. That's business as usual. But trading from (pick) 20 and above -- I don't know. The players are just so closely bunched -- at least in my mind -- that I'd be inclined to sit where I was."

Will Georgia running back Todd Gurley be among those players in the top 20 picks, or will he be in the last third of the first round that Polian references? Gurley's upcoming medical examination in Indianapolis to check on the status of his knee will provide that answer.

"I'm sure that everybody will be scrutinizing the results, and [teams] will all make their own decisions as to how far along the timeline he is," Polian said. "That decision, in my experience, rests with the [doctors]."

The primary question, Polian said, is whether the examination reveals structural damage from the ACL tear Gurley suffered last season.

"The answer to that question will lead many clubs to determine whether or not they take him in the first round," Polian said. "There's no question about his ability; there's no question about his work ethic; there's no question about anything football-wise. The question would be whether the knee would hold up over a five-to-seven-year career, let's say, just to pick a number."