Editor's note: This is the sixth in a series detailing the top senior prospects, by position, for the 2011 NFL Draft.
Did you know?
» Two of the best safeties of all time, Willie Wood of the Packers and Cliff Harris of the Cowboys, were both undrafted free agents. Both players were selected to All-Decade teams. The two combined for 77 interceptions, played in 14 Pro Bowls and won a combined four Super Bowls.
» In NFL Draft history, only one defensive back has been selected with the first overall pick (Gary Glick by Pittsburgh in 1956). Since 1996 the highest a cornerback has been drafted is third, when Seattle took Shawn Springs.
» Steelers defensive coordinator and football Hall of Famer Dick LeBeau holds the NFL record for most consecutive starts at cornerback (171). He played 14 seasons and started 185 games.
» Raiders cornerback Nnamdi Asomugha has the highest average defensive salary in the NFL, $28.592 million is guaranteed.
Defensive backs become more important every year because of the proliferation of the passing game. In 2008, 32 teams passed 16,350 times and ran 14,207 times. In 2009, they passed 17,033 times and ran 14,088 times (56.5 percent). In 1997 there were no 4,000-yard passers. In 2008, there were six. In 2009, 10 quarterbacks passed for over 4,000 yards.
Seven defensive backs were selected in the first round of the 2010 draft and a total of 12 overall in the first two rounds, including the fifth-overall pick and the seventh-overall pick of Round 1 (Kansas City's Eric Berry at five, Cleveland's Joe Haden at seven). Very seldom do we have two defensive backs picked this high.
The feeling around the NFL is that you can never have too many good cornerbacks. The key trait for this position is speed -- speed to break on the ball and the speed to turn and run with a wide receiver.
Height is also important due to the size of wide receivers.
Because of the empty backfield, one running back and multi-receiver sets, teams feel it's important to have three cornerbacks on the field a high percentage of the time in order to match up against all the fast wide receivers in coverage. Sometimes teams will have a third (slot) corner on the field as much as 75 percent of the time. The league average is about 64 percent.
The safety position seems to become more important every year, but it still ranks behind cornerback when it comes to the draft. In order to be a top safety, one needs to be a good tackler, as many teams now play eight defenders in the box against the run. You have to be a good blitzer and be able to cover big, fast tight ends. It also doesn't hurt to be a good special teams performer.
The two leaders in all-time interceptions -- Paul Krause (81) and Emlen Tunnell (79) were both safeties and are both in the Pro Football Hall of Fame.
This list only includes players who will have exhausted their eligibility after the 2010 season. Miami (FL) cornerback Brandon Harris, LSU corner Patrick Peterson and UCLA safety Rahim Moore are outstanding players but have two years remaining. For that reason they were not included on this list even though they would likely be top prospects if they chose to enter the 2011 Draft.
Here are the top 18 senior defensive backs scouts will be keeping a close eye on this fall.
Top senior defensive backs
Height/Weight: 6-foot 1/4, 200
Amukamara played as a true freshman in 2007. He did not make an interception in his first two seasons at Nebraska. He was a great high school athlete in Arizona and was a starting point guard on a state championship team. He was an Arizona player of the year in high school as a running back, rushing for 366 yards and four touchdowns in a playoff game. He was also the state high school track champion in the 100 and 200 meters. He has the size, quickness and toughness to play corner in the NFL. He is a top 10 pick in the 2011 NFL Draft.
Height/Weight: 6-1 1/2, 199
Dowling played as a true freshman but attended Hargrove Military Academy after high school, therefore he was an older true freshman than normal. He has very good athletic ability and speed, along with outstanding ball skills. He has eight interceptions in three years of college and will be a first-round pick.
3. Jimmy Smith
Height/Weight: 6-2 1/4, 200
Smith is a fifth-year player, who has four brothers that have also played college football. He has outstanding size and speed (4.45 seconds 40-yard dash). This is a very interesting player, who looks good playing on a poor team. He has first-round ability, but the 2010 season will have to tell.
4. Chykie Brown
Height/Weight: 5-11 1/2, 185
Brown is a fifth-year player, who has started 20 games over the past three seasons. He has exceptional athletic ability and has been well coached. He has coverage ability and solid ball skills. He has 4.5 40 speed and is also quite strong. Additionally, he has some special teams skills.
5. Brandon Hogan
College: West Virginia
Height/Weight: 5-10, 192
Hogan was a high school quarterback, who played wide receiver in 2007, before moving to defense and starting nine games in the secondary in 2008. He had 13 starts in 2009 and has four interceptions the past two years. He has speed and quickness, but was out of shape during spring practice and had an off-field problem. Despite those issues, his athletic and talent are unquestioned.
College: Ohio State
Height/Weight: 5-11, 190
Chekwa is a fifth-year player, who has started 25 games over the past two years. He ran the anchor leg of Ohio State's Big Ten champion 4-by-100 relay team. Scouts would like to see him make more plays (he had just one interception last year).
Height/Weight: 5-10 3/8, 191
Gilchrist will be playing cornerback this season after starting 14 games at free safety in 2009. He has played 902 snaps, the most ever by a Clemson defensive player. He was a highly recruited high school player and is a very good athlete with 4.5 speed. Last season, he finished second on the team in tackles, but did not have an interception.
College: Miami (Fla.)
Height/Weight: 6-0, 230
Van Dyke played and started eight games at cornerback in 2007 as a true freshman. He has 18 career college starts. Despite his thin frame, he has a willingness to stick his head in there and make the tackle. Not only does Van Dyke possess the athletic skills to be a good cover man, he can als return kicks. He needs to add bulk, but has 4.45 40 speed.
9. Davon House
College: New Mexico State
Height/Weight: 6-0 1/4, 188
House was a walk-on in 2007. He started all 13 games for the Aggies as a true freshman and has 9 INT. In three years, House led the WAC with 13 passes broken up in 2009. With one season to play, he has broken the school record for INT returns. He had better stats on defense than Kyle Wilson, who was picked in the first round of the 2010 draft.
10. Mario Butler
College: Georgia Tech
Height/Weight: 6-0 1/8, 182
Butler played as a true freshman in 2007 and has started 23 straight games at cornerback. He only has three interceptions in two years, and not many more passes defensed. New defensive coordinator Al Groh should help him tremendously.
11. Kendric Burney
College: North Carolina
Height/Weight: 5-9, 190
Burney has been a three-year starter for the Tar Heels, starting 38 games, and was named first team All-ACC in 2009. He had five interceptions last season, returning them for 200 yards (a school record). He has good ball skills and is a good athlete. Just as important, he also possesses a great attitude and is a hard worker. His height is a bit of a concern, but he may be better than several players ranked ahead of him.
12. Curtis Brown
Height/Weight: 5-11, 182
Brown played as a true freshman in 2008 and led the team in special teams tackles. He started 14 games in 2009 and had 15 passes defensed. He is an above average athlete with excellent ball skills, strength and speed. His versatility also makes him attractive.
13. Rashad Carmichael
College: Virginia Tech
Height/Weight: 5-11, 180
Carmichael is a fifth-year player, who did well as a full-time starter at corner. He had six interceptions and six pass break-ups in 2009, and is a very good competitor with 4.4 speed in the 40. He is a smart player with special teams ability and can help himself with a great 2010.
14. Jalil Brown
Height/Weight: 6-0 1/4, 201
Brown is a fifth-year player, who has started 15 games at corner (nickel). He has played safety as well and is a good athlete with the necessary toughness. He has under 4.5 speed.
15. Johnny Patrick
Height/Weight: 5-11, 185
Patrick is a fifth-year player, who was recruited as a wide receiver but moved to cornerback after his redshirt seasons of 2006. He started 12 games in 2009, and had two interceptions. He has quickness, good ball skills and 4.5 speed. He is an interesting player to watch in 2010.
16. Darrin Wells
College: Notre Dame
Height/Weight: 6-0, 183
Walls is a fifth-year player, who played as a true freshman in 2006. He started 11 games in 2007, but missed the 2008 season due to personal reasons. He started eight games in 2009, and has some intriguing skills.
17. Shareece Wright
Height/Weight: 5-10 3/4, 182
Wright started at corner in 2008 for the first two games of the season, but suffered a neck injury in practice and missed the rest of the year. In 2009, he was ruled academically ineligible, but he did return for the spring semester and played well in a bowl game. He has good cover skills, but his neck injury needs to be checked.
18. Shiloh Keo
Height/Weight: 5-11 1/8
Keo is a fifth-year player, who missed the 2008 season after shoulder surgery. He led his team in tackles in 2009 with 113 (34 more than the next highest tackler). He is a tough guy, with the ability to play safety and pick off passes (he has eight interceptions in three years). There are questions around his ability to cover NFL-caliber players.