Charlie Yook is the coordinating producer who oversees NFL Network's college football and draft coverage. We asked our resident college football "expert" to give us this season's top 50 college players, a list not based on film breakdown or pro potential, but one based on production and performance in college. Each week throughout the season, he will adjust his list and move players up and down and in and out based on their weekly performances. Think of it as an expanded Heisman Watch. This week he presents Nos. 21-30:
30. Ifo Ekpre-Olomu, CB, Oregon (junior)
I'm a big fan of this physical defensive back from Oregon. He might not be the biggest or fastest defensive back in college football, but man can he close.
» Watch: Ekpre-Olomu highlights
Gil Brandt's top five senior G/CsGil Brandt takes a look at the best college seniors at guard and center.
29. Cyril Richardson, OG, Baylor (senior)
His claim to fame was he protected Robert Griffin III's blind side during the 2011 season before being switched inside in 2012. He's like a living, breathing snow plow.
28. Loucheiz Purifoy, CB, Florida (junior)
Although the last guy who wore No. 15 at Florida generated more buzz, Purifoy is creating some of his own. He might be the best-conditioned athlete in college football, and the Gators plan on using him in all three phases -- defense, offense and special teams.
» Watch: Purifoy highlights
27. Cameron Erving, OT, Florida State (redshirt junior)
Last year was Erving's first year playing on the offensive line after coming to FSU as a defensive tackle. He did well protecting Buffalo Bills first-round draft pick EJ Manuel and practiced against the likes of Indianapolis Colts first-round pick Bjoern Werner and San Francisco 49ers second-round pick Tank Carradine.
26. Gabe Jackson, OG, Mississippi State (senior)
If Jackson were a bit nastier, he'd be ranked higher. He has all the physical tools, just needs to play more aggressive every snap.
» Watch: Jackson highlights
25. Ryan Shazier, LB, Ohio State (junior)
Every time I stepped away from an Ohio State game last year, I could still hear the announcers say "Shazier with the stop" or "Shazier with the play." I see similarities to Chicago Bears linebacker Lance Briggs.
24. Antonio Richardson, OT, Tennessee (junior)
This man held his own again South Carolina last year. That's impressive because South Carolina has Jadeveon Clowney. It's a deep year for talented left tackles.
» Watch: Richardson highlights
23. Brandon Coleman, WR, Rutgers (redshirt junior)
While he might not get as much publicity as USC's Marqise Lee, Clemson's Sammy Watkins or Alabama's Amari Cooper, don't sleep on Coleman. This big, athletic receiver has upside/potential written all over him. I expect a huge year from him.
» Watch: Coleman highlights
22. Bradley Roby, CB, Ohio State (redshirt junior)
As one of the best corners in the nation, Roby has all the talent in the world. He possesses confidence, toughness; Roby's a true lock-down defender. The big issue hovering over Roby is that he still is facing a misdemeanor charge of disorderly conduct and a one-game suspension.
21. Stefon Diggs, WR, Maryland (sophomore)
Terrapins head coach Randy Edsall has challenged Diggs to be more of a leader on and off the field. What you can't deny is that Diggs is a playmaker, whether it's by catching the ball, carrying the ball or returning the ball.
Charlie Yook is NFL Network's coordinating producer for "NFL GameDay Morning" and the NFL draft. Throughout the 2013 college football season, he will be providing regular commentary and insight on the college game and its players for NFL Draft 365. Follow him on Twitter @yookc.