NFL Combine 2012 Results: Tracking the Fastest 40-Yard Dashes on Final Day

We've already seen a number of blazing performances on the sideline track in Indianapolis, but there is a good chance the fastest numbers at the 2012 NFL combine come from the defensive back class on the field today.

LSU's Morris Claiborne is the class' consensus top player on the defensive side of the ball, but there is no clear-cut No. 2 behind him. Big names like Janoris Jenkins, Dre Kirkpatrick and Alfonzo Dennard are all on the field working towards earning that distinction.

The first group of defensive backs have started running, and the second group will be out soon. Here's a track of the day's fastest runners.

(All times are unofficial, as many would rather use the handheld times than the "official" times handed down by the NFL Network)

Group 1

Ron Brooks, LSU: 4.35

Any number under 4.4 is going to attract attention. At 5'10", 190 lbs., Brooks will certainly force teams back to the tape with this number.

Dwight Bentley, Louisiana-Lafayette: 4.37

The 5'10", 182-pounder turned heads with his times, and people are already talking about how much they love his hips (via Mike Loyko):

"

Other than Jenkins.. Dwight Bentley has the quickest hips and quickest peddle.. hes a player

— Mike Loyko (@NEPD_Loyko) February 28, 2012"

Jayron Hosley, Virginia Tech: 4.38

This is a great number for a kid with tremendous ball skills and experience. He was talked about as a potential first-round pick coming into the season, and this number will get teams to turn the tape back on.

Jamell Fleming, Oklahoma: 4.43

The Sooners corner checked in at 5'10 5/8", 206 lbs. Adding a sub-4.5 number to his previously rising stock is going to immediately give him another boost.

Janoris Jenkins, North Alabama: 4.44

The former Florida corner has made a strong case for No. 2 corner spot, and he strengthens that argument again here. The only thing holding him back is off-field concerns and maturity.

Stephon Gilmore, South Carolina: 4.44

This may be the most helpful number out of the first group. A shade over 6'0" and weighing 190 pounds, the fringe first-round talent may have solidified his place on Day 1 with this 4.44.

Morris Claiborne, LSU: 4.47

The draft's best corner just continues to do what everyone expects him to do: shine.

Trumaine Johnson, Montana: 4.50

This is a really solid number for the nearly 6'2", 204-pound safety. There are some interesting takes on his pro potential (via Shane Hallam):

"

Trumaine Johnson didnt look bad, his stiffness can be fixed, could play CB or S.Versatile

— Shane P. Hallam (@ShanePHallam) February 28, 2012"

Ace Jackson, Cal-Poly State: 4.50

The 4.5-flat is another solid number to add to Jackson's week. He measured in at 5'10", 191 lbs.

Charles Brown, UNC: 4.50

Shorter (5'9"), but stout (202 lbs) and now fast.

Terrence Frederick, Texas A&M: 4.50

All-around solid number for the Aggie corner who checked in at 5'10", 187 pounds.

Alfonzo Dennard, Nebraska: 4.51

This was a big number for the Big Ten Defensive Back of the Year. Dennard's top-end speed was called into question for most of the season and then exposed at the Senior Bowl. He obviously went back and did some work and looks unquestionably better than he did in Mobile.

Group 2

Josh Robinson, Central Florida: 4.29

Wow. That is all you need to say for this. He'll force teams to go back to his tape with the fastest unofficial 40 of this year's combine.

Bleacher Report's Matt Miller projects Robinson as a late-round pick:

"

@BleacherReport UCF CB Josh Robinson is projected as a 6th-7th RD player. Great athlete, poor ball skills. Very raw

— Matt Miller (@nfldraftscout) February 28, 2012"

Coty Sensabaugh, Clemson: 4.37

The cousin of Cowboys starting safety Gerald Sensabaugh, the Clemson corner promised Deion Sanders he'd run in the 4.3s, and he did just that. He's a great-looking athlete that teams will be interested in.

Jerron McMillian, Maine: 4.42

At 5'11", 203 pounds, this is a great number for the strong safety.

Dre Kirkpatrick, Alabama: 4.43

The lengthy Crimson Tide corner lived up to his billing. He's so long and athletic and now has a great time to pair up with his 6'1 5/8", 186-pound frame.

He's solidified his stock as a first-round pick.

Coryell Judie, Texas A&M: 4.44

The oft-injured Aggie needed a strong performance, and he got just that with this time. He couldn't stay on the field this year, but does have plenty of interest. He's a shade under 6'0" and weighed in at 194 pounds.

Trent Robinson, Michigan State: 4.46

The Spartan safety is smaller than most at the position (5'9 3/4", 195 pounds), so his sub-4.5 number was really important for him.

Kelcie McCray, Arkansas State: 4.47

Small-school safety prospect has great size at 6'1 3/4", 202 pounds and pairs it with a great sub 4.5 40 number.

Micah Pellerin, Hampton: 4.47

Another one of the many small-school guys, Pellerin has great size at 6'0", 194 pounds and length for the corner position.

Christian Thompson, South Carolina State: 4.47

Well-built safety's straight-line speed will earn him another look.

Sean Richardson, Vanderbilt: 4.47

At 6'2 1/2", 214 pounds, a sub-4.5 number is very impressive for the safety prospect. He's quite the physical specimen who also benched 22 times (third-best at the position) and broad jumped 10'8".

Chaz Powell, Penn State: 4.5

Solid all-around performance from the Nittany Lion corner this week.

Brandon Taylor, LSU: 4.5

Big safety who often looked like a linebacker this year for the Tigers.

Harrison Smith, Notre Dame: 4.56

Playmaking Irish safety backs up his rising stock with solid number for safety position. At 6'1 7/8", 213 pounds, he's a fringe first-round prospect.

You can catch me runnin' on Twitter too.