The value of an elite cornerback

The play of cornerbacks is one area in which college football differs significantly from you commonly see in the NFL.

Take Darrell Revis, the shining star of NFL Corner play. Revis Island won the 2009 AFC defensive player of the year award and has arguably been the cornerstone of Rex Ryan's Jets defense, which has ranked in Football Outsider's top 10 defenses every year of his tenure.

Rex Ryan employs an overall philosophy to defensive football that is similar to how his father Buddy Ryan approached the game with his 46 defense. However, his usage of zone-blitzes and overloaded concepts offers a greater variety of ways to attack what offenses are up to than simply packing the line of scrimmage like the 85 Bears.

Collegiate teams are adopting this strategy as well, however the constraints of what college corners AND quarterbacks are able to do means that the tactics are different.

For one, mobile quarterbacks make the threat of the overload blitz considerably less. If you overwhelm Tom Brady or Peyton Manning's protections, their only recourse are to throw emergency hot routes and hope to avoid turnovers or negative plays. If you were to use heavy doses of overload blitzes on Johnny Manziel you'd end up with a few sacks as small consolation for yielding the first 1,000 yard rushing game by a quarterback.

For another, Oregon's soft coverage on the outside and reliance on athletes like Ifo Ekpre-Olomu to close on short throws with big hits is not as sound a strategy against quarterbacks with NFL-level accuracy and wide receivers such as Hakeem Nicks or Calvin Johnson.

But college teams can rarely count on consistently having cornerbacks who can handle assignments such as demonstrated in this great write-up from our friends over at BucsNation.

By their nature, spread teams will look to use space to isolate their best players, but defenses rarely respond as below by allowing one of their corners to be left alone attempting to handle a precision spread passing attack.

In this instance, West Virginia is using this "Iso" package to get great matchups for their stud receiver on bottom, Stedman Bailey, and for the tailback Tavon Austin. The play here is a hand-off, but Oklahoma's response to the formation was to line up their star corner Aaron Colvin in press coverage against Bailey while dropping the right safety down to play in the box like a linebacker.

Consequently, Colvin has bracketed help inside but he's responsible for quick passes to the flat AND the vertical pipe. It's very rare for a college team to emulate the Jets in playing a corner in press coverage against an opposing team's star receiver with a single free safety who's shaded to the other end of the field.

Here the Mountaineers use play-action to attempt to punish the Sooners for this daring approach and throw the deep post to Bailey:

Most of the rest of college football doesn't have a cornerback who can be trusted to defend the quick slants, hitches, and comebacks against a top level outside receiver and be trusted to lock down the deep sideline against the go route or post like Colvin does here.

With this exceptionally difficult assigment, Colvin managed eight tackles, three pass break-ups, and an interception that undoubtedly were enormously important in securing a 50-49 victory. However, he also allowed Bailey to catch 13 balls for 205 yards and four touchdowns.

The number of ways that spread offenses challenge corners are numerous, and the better units are able to fully take advantage of all of them. Take Baylor's brutal assault they waged in 2012 with stud receiver Terrance Williams.

The first concern is the easy pitch and catch over the top:

Texas plays Quandre Diggs in press coverage on Terrance Williams, drops the safety to his side of the field down to stop Baylor's run game, and Digg's 5'10 (maybe) height combined with the deep safety's late arrival cannot prevent the 6-2 Williams from punishing them.

However, lining up the corner in soft coverage against a truly great outside receiver carries risks as well.

The quick hitch route or bubble screen to a powerful or elusive receiver against soft coverage and an overmatched corner can be about as easy a 5-7 yard gain as there is to be had in football.

There's also the quick slant inside:

Set up by a double move, Williams wins inside against the hapless Diggs.

Now combine them all together with Baylor's play-action game and you have a recipe that leads to this concoction:

Williams fakes the hitch route while Diggs' inside help from the safety is sucked inside by the play-action. In order to utilize the safety against Baylor's diverse options for attacking the middle of the field, Diggs has to control the deep sideline. However, he also has to come up and make that tackle on the easy hitch. Consequently, he bites on the double move and can't recover.

These are the challenges of a collegiate corner and they are different than in the NFL, generally requiring a more complete toolbox than your basic lockdown press coverage skills.

So what does an elite college cornerback look like and how is he utilized?

1. He can take away the sideline without assistance

For a defense to get the numbers back in their favor against today's terrifying world of spread-option attacks that make use of a mobile QB and packaged plays, great corners need to be able to stay on top of everything on the sideline without necessarily relying on safety help.

Trips formations with four wide receivers in particular often require that the boundary corner survive without deep safety help. This is a typical sacrifice defenses make, to trust their best cornerback to prevent the offense from beating them over the top without a safety to help out.

This allows the safety to fill backside pursuit angles against running plays, or chase down frontside runs that are spilled outside by the front. That can't happen if the defense can't trust the corner not to wet the bed against a deep route. That also can't happen if the corner is unable to handle the short passes he'll then frequently face, such as detailed above by Terrance Williams.

Some people call this "Quarters" but Cover-2 teams frequently switch between playing their boundary safety aggressively against the run and trusting their corner deep OR asking the corner to handle run duties and quick throws with the safety dropping back deep behind him.

There are also defensive schemes that count on the corner as a deep defender such as Cover-3 or Virginia Tech's Robber defenses. In these instances the team's better corner will need to handle deep responsibilities like a safety and demonstrate range against the pass in the deep field:

Or open field tackling against the run or completed short passes:

Virginia Tech's Antone Exum is pretty adept in these roles at 220 pounds, however his great upper body strength also comes in handy in completing assignment number two,

2. He can take away the quick game when backed by an end zone or safety help

For those times when a coverage provides deep help, or the situation calls for a defensive scheme that doesn't make the quick slant an appealing option, a good college corner has to be able to get physical and in the grill of a receiver to take away the freebies:

On the goal line it becomes virtually impossible to provide deep help from the safety due to the limitations of space and the need to protect more of the line of scrimmage from running plays. In these instances a team's best corner needs to take away the quick slant for a TD while also getting a good enough jam on the receiver to break up the fade route.

A defense that regularly relies on its corners to play press coverage without deep help on the sideline is going to struggle against today's offenses. The number of people on this world who have the physical abilities to mirror the best outside receivers and effectively jam them at the line without help are few enough and the necessary seasoning and training makes cranking them out routinely very difficult at the collegiate level.

That said, the ability to occasional press coverage is a necessary skill for a defensive scheme to have answers for every threat offenses bring to the field.

For cornerbacks playing on the boundary, which is typically where a defense will place the more physical and well-rounded back, the distance from the Quarterback is lessened, meaning that there's less time to react to the throw and a greater need to mix in tighter coverage to prevent too many easy short passes.

3. He's a weapon near the line of scrimmage

Typically a team's best corner plays on the boundary, where it's easy for an offense to get an isolated matchup for their best receiver to threaten every branch of the route tree ala Terrance Williams or Stedman Bailey.

However, this position on the field is also conveniently aligned to attack the run game or even blitz due to the proximity to the QB.

Jason Verrett is the best corner in TCU's loaded secondary and possibly the best corner in the Big 12 (Aaron Colvin and Carrington Byndom are preparing opening arguments) and his versatility is a sterling example of what college defenses are looking for in their best corners.

He begans the play in a press coverage alignment so as to dissuade Michigan St. from hitting them with a quick hitting pass play, but he drops back before the snap indicating that the safety behind him is the boundary defensive back with run stopping responsibilities while Verrett is in charge of job #1 for a great corner: handling the deep sideline without assistance on vertical routes.

As it happens, Michigan St's inside run sucks the safety (Hackett) inside and unable to stop Bell from bouncing outside for a potentially big gain. Verrett plays the role of a Cover-2 safety in responding to the run and making a tackle for a minimal gain. Because he's good enough in coverage to play the sideline without bailing into a deep alignment immediately, and because his reaction time and speed are both good, Verrett makes this play much closer to the line of scrimmage than your average Cover-2 safety lined up 15 yards off the ball.

Then there are the possibilities as a blitzer:

This is a Fire Zone call that most defenses are incorporating, bringing either the nickelback or the boundary corner off the edge from an outside angle that is very difficult for an offensive tackle to pick up. It can yield both blindside hits on the quarterback as well as tackles for loss against running plays as above.

A great boundary corner provides a defense with the option to 1) Leave him without deep help on the sideline and allow the safety to play downhill 2) Press him against the outside receiver in Cover-2 or in the Red Zone to take away quick passes 3) Use his proximity to the ball to make the boundary impossible to run on or even blitz into the backfield.

The field corner has to deal with abundant space and vertical route combinations but is rarely left alone or asked to be a presence in the box. The nickelback has a similar role in taking away quick throws and playing near the box but is never faced with taking on vertical routes without deep help.

The boundary corner position is typically where the elite collegiate DB is deployed, save for those teams that play their corners left and right rather than field vs. boundary to combat tempo. In this instance, the better player lines up to the right.

4. Erase your half of the field

Most defenses don't ask any more than 1-3 from their best corners, but if you have a deserted island with which to imprison criminal masterminds such as Terrance Williams, then by all means, banish them to it. If a college team finds someone who can play press coverage without shaded safety help then you'll see some the spread offense brought down to size at last. Of course, the necessary film study and technique to achieve this result is typically beyond even the greatest student athletes.

However, every once in a while the college game will produce someone so polished and dominant that offensive coaches are better off shrugging and avoiding throwing the ball anywhere near them. When you can't throw the ball at someone for fear if giving up points, that's when a corner reaches the final tier of excellence. In reality, it isn't that common at any level of the game and certainly not in today's college game.

However, great players that can accomplish steps 1-3 and free up their teammates to handle the stresses of modern offenses are still worth their weight in gold. There's the mark of an All-American, Thorpe award winner, or maybe even a Heisman.