Detroit Lions at Chicago Bears

The Lions found Larry Warford in the third round of last year's draft, and he's blossomed into a full-time starter right away. (Mike Mulholland | MLive.com)

(Mike Mulholland)

The Detroit Lions have done their homework for a possible trade into the top five of next week's NFL draft.

That includes hosting Jadeveon Clowney, Sammy Watkins and Khalil Mack, each of whom is considered the best player at his position.

But is any of them worth the price that will be required for a trade up?

Fewer picks means fewer opportunities to draft starters. And that's not how many of the NFL's best teams have been built.

"If you look at the top teams in the league -- the teams that are consistently winning in the National Football League -- they're the teams that are drafting well," ESPN draft analyst Todd McShay said Wednesday on a conference call with reporters. "They're not giving up picks, they're not going three years without a first- or second-round pick like Carolina did.

"They're not jeopardizing nine first- or second-round picks like Washington did over a seven- or eight-year span. Those are the teams that bounce up and down and they really have to rely so much on free agency they wind up overpaying."

The Green Bay Packers are the paragon of McShay's philosophy. They lead the NFL with 33 homegrown players on their roster, and are a perennial playoff contender.

The Falcons, 49ers, Ravens and Bengals follow with 30 active players they drafted, while the Patriots are at 29.

Detroit has 27.

Quite simply, rookies are cheaper. So hitting in the draft builds depth cheaply, which frees up funds for free agents.

McShay says the magic number is three.

"If every year you draft three solid or great starters, you can replace your roster and keep it rolling," McShay said. "The teams that have four are usually the teams in the playoffs just about every single year."

The Lions had that kind of success last year.

They got a productive starter at No. 5 overall in Ezekiel Ansah. But they also got a starter in the third round (right guard Larry Warford) and fifth round (punter Sam Martin), plus part-time starters in the second round (cornerback Darius Slay) and in the undrafted free-agent market (offensive tackle LaAdrian Waddle and tight end Joseph Fauria).

Detroit also is high on fourth-rounder Devin Taylor, a promising defensive end.

That was a heck of a haul -- perhaps the best in the NFL -- and helped fortify multiple positions of weakness in a single year.

And that serves as a reminder that while a trade up for Clowney, Mack and Watkins would make major waves on draft day, it can be the depth of a draft class -- and not its headliner -- that determines the long-term success of a franchise.