The defensive-back position can be one of the toughest to evaluate because the measurables are so closely grouped.
A matter of inches and pounds can make you "undersized." Not tenths but hundredths of a second can make you "slow."
For corners, the amount of tackles you rack-up are not as important as your tackling ability. For safeties, interceptions are impressive, but scouts really want to see if you can get your nose into every play.
Every year defensive backs fly up the draft board with impressive combines. While athleticism is very important, if you're constantly resorting to your elite speed to make-up for poor positioning, you probably don't deserve to be on the field.
Right now it looks as though there are two cornerback prospects that are locks in this year’s draft.
Both Vontae Davis and Malcolm Jenkins have very high floors that they have established with their play on the field, and high ceilings due to their astonishing physicals.
Malcolm Jenkins, Ohio State, 6'0 1/8", 204, 4.55
Many scouts were looking down on Jenkins' forty times at the combine, suggesting the two-time All-American corner would have to switch to safety. To me, the fact that he can play safety is a testament to his versatility and physical football skills.
In his Pro Day, he posted similar forty times to the combine. A sub-4.6 40 is not too slow to be a No. 1 corner when you're big and technically sound.
The best NFL comparison to Jenkins is Antrel Rolle of the Arizona Cardinals who was drafted eighth in 2005 as a corner and later switched to safety.
Vontae Davis, Illinois, 5'11 1/8", 203, 4.49
Entering the NFL Draft process, Vontae Davis had some big shoes to fill. His brother Vernon, of the 49ers, had one of the best combine performances ever and it propelled him to the sixth pick in the 2006 draft.
Vontae's combine wasn't as impressive but he didn't disappoint, and at his March 18th Pro Day he dropped his forty time to 4.35 seconds.
It's not just Davis the athlete teams are after. He has held two of the top receivers in this year’s draft, Jeremy Maclin to six catches for 74 yards and Brian Robiskie to six catches for 40 yards in two games each.
You don't have to be a first-day pick to be one of the best in the business. At the 2009 Pro Bowl, there were six defensive backs that were picked in the third-to-seventh rounds.
Clearly those players were underrated during the draft process, but how did it happen?
Many times these underrated defensive backs either haven't played against tough enough competition in college or they have a glaring hole in their height or speed.
This year Victor Harris, Sean Smith, Joe Burnett, Chris Owens, and Kevin Ellison are five of the most underrated defensive backs in the draft.
Victor "Macho" Harris, Virginia Tech, 5'11 1/4", 198, 4.63
Got swag? Macho does, and with 15 interceptions and four touchdowns in three seasons you would too.
Harris isn't a burner but he has enough speed and size to get the job done at the next level. Teams that play a lot of man coverage should stay away from Harris, as he excels in zone schemes where he can read the field.
Macho has great ball skills and body control. He can deflect passes that should be caught and if he gets two hands on a ball it’s going the other way, potentially for six points.
For better or worse Victor "Macho" Harris shares some similarities in his game with another infamously nicknamed corner, Adam "Pacman" Jones. Both have big-play potential on defense and special teams and they thrive in pressure situations.
Harris was involved in a shooting that took place at his apartment in 2007 but it appears he was only a bystander. He has also let his emotions get the best of him on the field at times.
There is risk involved with this pick but for a team that has had trouble coming up with big-plays in the secondary, Macho is a very attractive prospect.
Sean Smith, Utah, 6'3 1/2", 214, 4.53
Most receivers Smith's size have trouble getting in and out of their breaks so as a converted-corner it's very impressive that Smith is able to cover smaller opponents.
His quickness is not his strong suit, however. Smith is a ball-hawk who attacks balls as if he was still playing WR. After interceptions, he instantly clicks into an offensive mindset and looks for the end zone.
Smith's aggressiveness, size, and ball skills will allow teams to try him at safety and he can make an immediate impact guarding some of the leagues larger receiving targets.
Joe Burnett, Central Florida, 5'9 3/8", 192, 4.57
Every team will pass one Burnett for three-to-five rounds and during the season 31 teams will be asking why they passed on that guy.
Early in his career don't expect Burnett to be on the field as an every down, shut down corner. The special teams is where the All-American return man will make his presence felt.
Burnett is not a great straight-line runner, but in-space he is very quick and he will elevate over receivers to intercept passes.
Coye Francies, San Jose State, 6'0 3/8', 185, 4.56
With Francies, we are looking at a guy who's played a lot of football in a lot of different places.
In 2005 he was a CC All-American with American River College in California. He then transferred to Oregon State where he returned kicks and started five games at corner. He was also arrested for illegal weapons possession, which led to a dismissal from the team.
In two years at San Jose State, Francies registered 105 tackles, four interceptions and three forced fumbles, very impressive stats for a corner. Teams were delighted by Francies' practice and play at the East-West Shrine game, where he competed against top-competition.
He will slip in the draft due to his history, but for the team who can look past his past they are getting one heck of a football player.
Kevin Ellison, USC, 6'0 7/8", 227, 4.85
The biggest safety in the draft, Ellison's speed is not as big an issue as his forty time might suggest. His safety play was lost amongst the stars at USC but he is a very fluid pass defender that will come up and make the knock out blow.
Teams have talked about playing Ellison up in the box as a hybrid linebacker/safety and don't be surprised if he lands in New England because of his run-stopping ability.
Highlights go a long way for defensive backs. One or two great interceptions returned for touchdowns will have some teams’ believing you are the next Dion Sanders.
An overrated player might not necessarily be a bust in the NFL but if you are a corner selected in the first round within a few seasons you should be able to stand out on an island with any receiver in the NFL.
Alphonso Smith, D.J. Moore, Captain Munnerlyn, Asher Allen, and Patrick Chung are five prospects where the math just doesn't add up.
Alphonso Smith, Wake Forest, 5'9", 193, 4.52
You don't have to be a giant to be a successful corner in the NFL but if a team is going to make Smith a mid-to-late first round pick they will expect him to stick the likes of Larry Fitzgerald and Calvin Johnson.
An undersized corner must be blazing fast and that means breaking the 4.50 mark, something Smith could not do.
This year against Maryland, speedster Darrius Heyward-Bey caught 11 passes for 101 yards and a touchdown against Wake Forst, his best performance of the season by far.
To Smith's defense, he did record 21 interceptions in his career including a 2007 interception for a touchdown against Matt Ryan.
He should be a second-round pick in the draft and projected as a good No. 2 corner.
D.J. Moore, Vanderbilt, 5'8 7/8", 192, 4.53
Is there an echo in here? How is a corner under 5'9" with a slightly above-average 40 expected to stick Randy Moss for four quarters?
Moore was a tackling machine in three seasons at Vandy recording 179 to go with his 12 interceptions but ability is not what's in question, it's size. He just won't be big enough to stop the NFL's bigger wide outs in the red zone.
Moore is a gambler who is quick to jump passes and it paid-off in college. In 2008, he intercepted Matthew Stafford, but the top receiver he faced was Jarrett Dillard who registered seven catches for 105 yards.
Much like Smith, Moore is a good corner who will struggle against the top-tier of receivers in the NFL.
Captain Munnerlyn, South Carolina. 5'8 1/2", 182, 4.52
If Captain's last name was Bailey instead of Munnerlyn, I might have more faith in his NFL potential.
Once again, we have an undersized corner without elite speed. The biggest problem is that Munnerlyn doesn't display the play-making ability that his undersized counterparts do.
Captain can mirror most routes but he doesn't display great closing speed when the ball is in the air. This will lead to a lot of plays where Munnerlyn is in position but lacks the ability to disrupt the pass.
Asher Allen, Georgia, 5'9 1/2", 194, 4.53
Allen is the cornerback prospect who would have benefited the most from returning to school. Right now he is a very average prospect who doesn't do anything special.
He is not a playmaker, isn't physically imposing, and isn't especially fast. Allen could make a fine career for himself as a nickel back but he is the defensive back who ceiling is closest to his floor.
Patrick Chung, Oregon, 5'11 1/4", 212 pounds, 4.54
Safeties that can lay-hat get a lot of attention. In film sessions, safeties that are always looking for that big hit also get chewed out for missing tackles. Chung is guilty of being over aggressive in the running and passing game and while this tactic can work in college he will end up whiffing a lot in the NFL.
If you throw the ball at Chung he will catch it, just don't expect him to make any spectacular plays on the ball in the secondary.
While he is fast enough to stick with most receivers he lacks the quickness to cover slot guys and lacks the height to shutdown the bigger tight ends in the NFL.