How NFLDraftScout.com ranks the top five defensive prospects at each position entering the combine. Prospects are listed by name, school, weight/weight/speed/projected round. Underclassmen denoted with an asterisk.
1. *Da'Quan Bowers (Clemson) 6-4/275/4.64/1
Led the nation with 15.5 sacks, but he isn't just a speed threat off the edge. Bowers' size and strength make him a complete defensive end worthy of consideration as a top five pick.
2. *Robert Quinn (North Carolina) 6-5/268/4.64/1
A more explosive edge rusher than Bowers, Quinn has to answer questions potential employers have about his year-long suspension if he is to receive the top 10 grade his athleticism and upside warrants.
3. Cameron Jordan (California) 6-4/287/4.85/1
A first-team All-Pac-10 defender, Jordan entered the Senior Bowl underrated. He left as one of the hottest names participating in Mobile.
4. Adrian Clayborn (Iowa) 6-3/286/4.79/1
Didn't enjoy the same production as a senior that he did in 2009, but scouts nonetheless love his strength, active hands and instincts.
5. *J.J. Watt (Wisconsin) 6-6/292/4.87/1
A former walk-on tight end, Watt has built himself into the ideal 3-4 defensive end candidate with strength training and a high-revving motor.
1. *Nick Fairley (Auburn) 6-4/298/4.92/1
The most physically talented player in the draft, Fairley's burst and flexibility make him an ideal three-technique defensive tackle in the 4-3 alignment. If he can ease scouts' concerns about an inconsistent motor, he could wind up the No. 1 pick of the draft.
2. *Marcell Dareus (Alabama) 6-3/309/4.95/1
Powerful and versatile enough to compete at any position in either scheme, Dareus' versatility and consistency could make him a top-five selection.
3. *Corey Liuget (Illinois) 6-3/300/5.12/1
His explosive burst off the snap and good strength to fight through blocks are helping Liuget prove to scouts that he's a legit first-round talent.
4. Stephen Paea (Oregon State) 6-1/295/4.98/1-2
A two-time winner of the Morris Trophy as the Pac-10's most dominant defensive lineman, Paea's lack of size and the fact that he made a lot of effort plays at the college level -- as opposed to consistently overwhelming blockers with explosiveness, overwhelming power or agility -- has scouts concerned about which position best suits him in the NFL.
5. Phil Taylor (Baylor) 6-4/337/5.26/1-2
A dominant run-stuffing presence inside, Taylor impressed at the Senior Bowl and could land in the first round if he can convince scouts he's past immature mistakes that forced him to transfer from Penn State.
1. *Martez Wilson (Illinois) 6-4/250/4.59/1-2
Blessed with prototype size and athleticism for the position, Wilson could take over games at the college level. Scouts want to see more consistency from him, but he has the physical tools to become a better pro player than he ever was for the Illini.
2. Greg Jones (Michigan State) 6-0/240/4.64/2
A three-time first-team All-Big Ten selection, Jones was as productive and consistent as they come for the Spartans. His marginal size will be a greater concern for NFL teams and means he'll need to be protected up front or be moved to an outside LB position.
3. Quan Sturdivant (North Carolina) 6-2/230/4.63/3
Lacking the name recognition many of his former teammates boast, Sturdivant could be a top 100 pick based on his all-around play.
4. Colin McCarthy (Miami, Fla.) 6-1/235/4.67/3-4
Not an elite athlete, McCarthy's instincts and physicality stood out at the Senior Bowl and could ultimately result in a more productive career than some more highly touted peers.
5. Kelvin Sheppard (LSU) 6-2/250/4.64/4
A versatile defender asked to line up in a variety of roles for the Tigers, Sheppard is one of the few linebackers in this class with the athleticism and instincts to play in the middle of the 4-3 and the size and physicality to handle inside linebacker in the three-man front.
1. Von Miller (Texas A&M) 6-3/237/4.56/1
The Butkus Award winner as the nation's top linebacker, Miller impressed scouts at the Senior Bowl to the point that he might have emerged as the top senior prospect in the draft with his spectacular showing there.
2. *Aldon Smith (Missouri) 6-4/258/4.69/1
A defensive end for the Tigers, Smith's lanky frame and impressive athleticism make him an intriguing candidate as a rush linebacker in the 3-4 alignment. Only a redshirt sophomore, Smith is just scratching the surface of his potential.
3. *Akeem Ayers (UCLA) 6-4/255/4.68/1-2
Ayers is a physical specimen. His size and athleticism is sure to wow scouts in workouts. He has proven he has the ability to make big plays, but some scouts question his pure instincts for the position.
4. *Justin Houston (Georgia) 6-3/258/4.73/1-2
The SEC's leading sack artist and one of the few pass rushers with experience at defensive end and outside linebacker, Houston's burst off the edge is sure to intrigue teams needing standup rushers.
5. Brooks Reed (Arizona) 6-3/257/4.53/2-3
Another former defensive end, Reed's burst off the edge makes him a logical candidate to move to rush linebacker for the 3-4 alignment. A strong week of practice at the Senior Bowl has his stock on the rise.
1. *Patrick Peterson (LSU) 6-1/212/4.42/1
He bagged almost every award for which he was a finalist -- Thorpe, Bednarik, SEC Most Valuable Defender and Special Teams player. Frankly, Peterson is more decorated than a wedding cake. He's also considered by some scouts to be the best cornerback prospect since Darrelle Revis and a legitimate candidate to go No. 1 overall.
2. Prince Amukamara (Nebraska) 6-0/205/4.49/1
A former running back, Amukamara's blend of size and speed earned him the top grade by pro scouts among all senior prospects entering the year.
3. *Brandon Harris (Miami, Fla.) 5-11/195/4.45/1-2
In a draft blessed with cornerbacks of great size, Harris might have the quickest feet. His cover skills should push him to the first round -- though a poor showing against Notre Dame's Michael Floyd in the Sun Bowl didn't help his cause.
4. Jimmy Smith (Colorado) 6-2/205/4.49/1-2
If Smith starred for one of the Big 12's high-profile teams rather than lowly Colorado, he might be universally recognized as one of the draft's elite defenders. Instead, he ranks as one of the more underrated and a potential top 20 draft pick.
5. *Aaron Williams (Texas) 6-1/195/4.49/1-2
Williams wasn't aided by a down year for the UT program, but he possesses the size and athleticism that every NFL team is looking for.
1. DeAndre McDaniel (Clemson) 6-0/213/4.54/2
A versatile playmaker at his best when facing the quarterback, McDaniel's instincts and ball skills stand out in a relatively weak class of safeties.
2. Ahmad Black (Florida) 5-9/183/4.51/2-3
If Black was 6 feet tall, he'd be the unquestioned top safety in this class. No doubt, he'll find a spot in the NFL. Some teams view Black as a possible cover-2 corner due to his reliable open-field tackling and quick feet.
3. *Tyler Sash (Iowa) 6-1/210/4.59/3
A heady defender with big-play credentials, Sash could enjoy a strong rise up the board if he works out well.
4. Joe Lefeged (Rutgers) 5-11/208/4.58/4
He's not the playmaker former Scarlet Knights CB Devin McCourty is, but Lefeged's ability to impact the game on defense and special teams is reminiscent of the Patriots' 2010 first-round pick.
5. Jeron Johnson (Boise State) 5-10/211/4.53/4-5
A three-time All-WAC defender, Johnson's athleticism and reliable open-field tackling skills could make him a late-round gem.
1. Quinton Carter (Oklahoma) 6-1/211/4.57/2
Quick to attack the line of scrimmage, Carter is an intimidating hitter and reliable tackler. If he wants to remain at free safety, he'll need to prove he has NFL-caliber speed.
2. *Rahim Moore (UCLA) 6-1/196/4.50/2-3
Dropped from an NCAA-leading 10 interceptions in 2009 to only one in '10, but his length and agility make him arguably the best coverage safety in the draft.
3. Jaiquawn Jarrett (Temple) 6-0/196/4.57/3
Opened eyes with a strong week of practice at the Senior Bowl, but Jarrett, like Carter, might have to run well to ease concerns from scouts about his speed.
4. *Jerrard Tarrant (Georgia Tech) 6-0/205/4.53/3-4
Stepped up in the absence of Packers third-round pick Morgan Burnett, emerging as one of the better coverage safeties in the country.
5. Chris Conte (California) 6-3/212/4.54/4
A former cornerback who starred this season in his first extensive duty at free safety, Conte is quietly viewed by some teams as this year's top senior at the position.