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Rick Scuteri/Associated Press

We don't like to think about what the NFL will look like without defensive backs like Darrelle Revis or Charles Woodson—or even underrated studs like Terence Newman—but it will happen. And it'll happen soon.

My generation didn't want to think about a NFL without Deion Sanders or Ronnie Lott, but along came the next wave of talent in the form of Champ Bailey, Woodson, LeRoy Butler and more. We didn't want the game without Darrell Green or Rod Woodson, but along came Earl Thomas and Richard Sherman. No more Deion? Here's Desmond Trufant. The game moves on, and legends walk away. Looking ahead to the next generation, who will be the best defensive backs in the year 2020?

That's what this signature series aims to answer. Our "20 for '20" covers who the top 20 defensive backs will be five seasons from now. And if you're looking for guys like Revis or Kam Chancellor—who will be well over 30 years old in 2020—we have to project a few retirements and a few slowdowns.