Film Room: Understanding Cornerbacks

by Andy Benoit

The trade that sent Asante Samuel from Philadelphia to Atlanta this past offseason was a little odd. It’s not often we see a player sign a three-year, $14.5 million contract upon being dealt for a measly seventh-round pick. That’s a lot of money for a player whose worth was deemed by his former team to be almost nothing. In some ways, it's a fitting transaction for Samuel. Not because the 31-year-old might be in steep decline, but because he’s always had a unique sort of value.

Samuel excels in FO's game charting metrics, and he has long been regarded as one of the best off-coverage corners in the NFL, but an "off-coverage" corner is all he is. Telling a corner he’s great in off-coverage is somewhat of a backhanded compliment –- like telling someone they are a lot of fun when they're drunk. (Thanks! ...Wait ... only when I’m drunk?) Samuel’s strengths include identifying route designs and making breaks on the ball. His weaknesses are jamming receivers at the line, bump-and-run plays that are headed downfield, responding to sudden changes of direction, and anything remotely related to tackling. There is practically zero physicality to his game.

Samuel in a nutshell: a great playmaker, but a limited one. A corner that specializes in off-coverage is generally someone who is good in zone and iffy in man-to-man. When they do play man, it’s almost always off-man, which is essentially man coverage with a cushion. In that design, the corner’s aim is to keep the receiver in front of him and the quarterback in his line of vision.

Most zone corners plays off-man regularly each game, as virtually every type of coverage, with the exception of a classic Cover-2, involves some sort of man principles. A great example is Cover-3, a coverage in which the outside corners each take a third of the field while the deep safety handles the middle. In a Cover-3, it makes no sense for a cornerback to just line up and guard the grass in his area, as quarterbacks not named Donovan McNabb don’t randomly throw at grass. The corner’s job, rather, is to locate and defend any receivers who come into his area.

Because they’re usually able to see the quarterback, off-coverage corners are often the ones making interceptions. The great ones disguise their intentions and bait quarterbacks into throws. Few players have done this as well as Samuel, and consequently, quarterbacks have developed a healthy fear of throwing to his side of the field. Analysts usually feel smart pointing out that "Joe Quarterback hasn’t even thrown to Samuel’s side this game." Too often, though, their follow-up comment involves mistakenly designating him as a "shutdown corner."

Samuel is not, and has never been, a shutdown corner. On one out of every five occasions, Samuel might jump a pass and either knock it down or take it back for six. But with his perpetually soft cushion, a great quarterback knows that he could, theoretically, go after Samuel. He could do that by throwing at him, but the offense also could run at him and manipulate other play designs to capitalize on his distinct weaknesses. What’s more, those distinct weaknesses hinder how Samuel’s coaches use the defensive backs around him. It can be very tough to sprinkle variety into your defense when one of your corners constantly plays with a soft cushion. This is why Samuel's value doesn't match the numbers he puts up in FO's game charting metrics. Yes, Samuel has led all starting cornerbacks in Adjusted Yards per Pass for two straight seasons, but his style of play opens up ways for the offense to get yardage in other ways.

You could argue that Samuel’s opposite is Nnamdi Asomugha. The ex-Raider is an elite press-man corner who struggles in off-coverage. Asomugha’s long, sturdy frame and fluid change-of-direction in a backpedal have made him a great man-to-man defender. But Asomugha doesn’t move well when coming from a standstill; he doesn’t react with a quick twitch to things he sees. (The Eagles, amazingly, didn’t seem to recognize this last season when they played him in the slot and at dime linebacker, but that’s another discussion.)

While Samuel has to be reactive in his coverage, Asomugha has to be proactive in his. Asomugha can shadow a receiver, but the catch is that he’s got to be able to exert some physical influence over where that receiver goes. It’s not just about getting jams and pressing –- it can’t be, given how the NFL frowns on physical coverage downfield. Asomugha has to influence receivers with his positioning. His goal is usually to force a receiver towards the sideline. That gives a receiver less area to run his route, which makes him easier to shadow. Cornerbacks who rely on using the sideline to their advantage are often referred to as "boundary corners." Asomugha is the best boundary corner in the NFL.

Perhaps it was erroneous earlier to refer to Asomugha as "an elite man-to-man defender." Really, he’s elite in man-to-man on the boundary side of the field. Playing pure man-to-man in space, Asomugha is merely very good. That still makes him one of the game’s best, but there’s a notable difference between his ability on different sections of the field.

Very few cornerbacks are truly elite in pure man-to-man. That’s why it is so hard to find quality nickel backs. A cornerback covering the slot almost has to play man-to-man because it’s too difficult to clearly identify and defend zones in the short middle of the field.

Due to the difficultly of consistently shadowing NFL receivers, a lot of slot corners play a trail technique in man, which basically means they stay on a receiver’s hip pocket. This kind of coverage requires safety help over the top. It’s very liberating for the corner, as he has room to recover from his mistakes and, unlike a boundary or zone corner, he doesn’t have to operate out of a backpedal.

What’s rare is finding a cornerback who has the recovery speed and innate positioning prowess to play trail and still make plays on balls thrown over the top. The guys who can do this are the elite man-corners -– the ones coaches are willing to occasionally put on an island with no safety help ( Champ Bailey, Joe Haden, Johnathan Joseph, Ike Taylor, to name a few). Often, but not always, the same athletic traits that give a player great recovery speed are the same athletic traits that allow him to effectively break on a ball. Thus, the elite man-corners can usually thrive in zone.

Elite man-corners are not shutdown corners, though. Shutdown corners are the guys who can play all types of coverage against all types of receivers. They’re the guys defensive coordinators build entire schemes around. Often, really good man-corners, particularly the physical ones like Ike Taylor and Johnathan Joseph, can look like shutdown corners because their coaches will build schemes that put them in isolation coverage. However, the coach does this figuring the corner will surrender five or six completions -– a worthy tradeoff for the freedom of having 10 guys to use elsewhere. A coach with a shutdown corner, on the other hand, assumes his superstar will give up no more than one or two inconsequential completions a game.

Generally, shutdown corners play man-to-man because a) It’s a straightforward approach that suits their ability and b) They don’t have any safety help, so they have to play man. Sometimes that man coverage is a Samuel-styled off-man, sometimes it’s an Asomugha-styled press near the boundary. Most often, though, it’s in the form of trail technique, as that’s easiest and best way to prevent passes from even being attempted. The true shutdown corners have the recovery prowess to play trail technique with no safety help.

Currently, there is only one shutdown corner in the NFL. His name is Darrelle Revis. But, there may be a second in the making in Arizona: Patrick Peterson. The No. 5 overall pick of the 2011 draft drew plenty of shutdown assignments late last season. Remarkably, he played trail technique almost exclusively, even on the outside, where off-man or press-boundary usually prevail. Peterson has unwavering faith in his recovery ability.

The takeaway here is that not all highly-regarded cornerbacks are equal. It’s very difficult, perhaps even impossible, to find statistics that accurately portray a corner’s true value. There are just too many variables in the actual playing style that can't be properly expressed through numbers, so any advanced metrics need to be seen in context. Samuel has been to four Pro Bowls; Taylor has been to none. Samuel is the more dangerous player, but Taylor has allowed his team to do more schematically. It's my guess that most coaches would rather have Taylor than Samuel.

When evaluating cornerbacks, instead of focusing simply on how the guy is playing, focus on how he is being used. That will tell you a lot about him.

Follow Andy Benoit on Twitter: @Andy_Benoit.