A Dummies Guide to Cornerbacks

Today's installment of the Football FAQ is a look at corner backs. Arguably the most important asset for a defense, a good corner is hard to find. The rules work against them and there is quite a lot of knowledge of the offense required to play well.

The general concept of the cornerback is to, as I was taught when I was little, "legally interfere with the catch." They do this by playing different coverages and playing to their assignment. But there is so much more to it.

Asante Samuel may be one of the NFL's best cornerbacks.
Making a good corner

Cornerbacks generally are the quickest and most athletic players on the team. This is for a reason. They need to be able to chase speedy receivers, keep up with them, and be able to correct themselves quickly when beaten on a double move or a misjudgment on the route.

They need to be able to be athletic enough to get in front of a receiver before the ball gets to him; that means agility and recovery speed, not just pure straight line speed. Not to mention, they must jump high enough to compete for the football.

Even if a cornerback has all those skills athletically, they still need to be able to tackle in the open field, or at least slow down the carrier enough for someone else to clean up.

And of course, you need to be very smart and alert. Corners must locate the ball while reading and reacting--to the point of being proactive--to everything that the quarterback and wide receivers do. This takes amazing work ethic and willingness to study every aspect of the opposing team, looking for anything that will tip you off on what is going to happen and how to stop it.

Basic skill set

There are some basic techniques and skill sets that corners need to possess. In this case, many of the techniques are skills in themselves.

1. Backpedaling: The basic technique all corners need to be good at. This keeps the play in front of you while still being able to keep an eye on your man or any receiver entering your zone.
2. Shedding blockers: Corners need to do this, too, and especially if you expect to stop some speedy outside runners. Luckily, it's mostly receivers they will need to beat off a block.
3. Physicality: Nowadays, the rules are against the cornerbacks. They only have five yards in which to interfere with a receiver in any way (in high school and even to some extent in college, you are allowed to keep an arm, hip or back against a receiver, but cannot grab or push). This makes it much harder to to keep track of the receiver when beaten, and thus it's becoming a bigger necessity to be as physical as possible within the five yards. This disrupts the route's timing and flow. Physical play when going for the ball without interrupting the receiver is also a big plus.
4. Man up bumping: A separate skill from purely being physical at the line. This is the ability to force a receiver, from the bump, to go outside or inside and completely adjust their route. Only the real best of the best (with physicality) can do it this well.
5. Tackling: A corner who can't tackle is a huge liability, especially against the short passing game in which he may get beat for lots of 2 or 3 yarders that turn into first downs on a failure to wrap up.
6. Sudden explosiveness: The ability to make quick adjustments and "burst" into the play. Explosiveness is necessary for getting in front of a receiver before the ball does without impeding the intended target, blitzing, making up for a misjudgment of the route, or recovering from a lost step to stop the receiver when he slows just enough to make the catch.
7. Speed: Plain and simple, they need to be able to run with at least the worst-of-the-best of them.

Reading and reacting

It's preached to corners from the high school to pro levels by any defensive coach: watch everything. Maintain focus on the play. Be aware of what the quarterback and receiver are doing. React to what you see as quick as you can.

It sounds simple. At the pro level though, with all the confusing variables the offense will throw at a defense, it becomes extremely difficult. Luckily enough (or maybe not so, depending on the work ethic of the corner), at the pro level, there is plenty of time for film study with school studies done. But the same goes for the offense, who will be tipped off about your coverage by anything you do as well. So reading and reacting, again, becomes even more crucial and difficult.

Cornerbacks need to react to everything the quarterback does without biting on any form of misdirection play--be it a counter, a draw, play action or pump fake--while still keeping tabs on anything the reciever is doing to get an idea of where they are doing with their route, when to break on it, or deciding keep the play in front of them instead of breaking on the route. Some coaches preach different aspects of this for their defense, preferring their corners play aggressive and break early, while some demand their corners never break and always keep the play in front of them (usually zone defenses).

Aggressive and conservative corners

Depending on the coaches preference, the cornerback will either play aggressive, meaning break on the route (jumping it for a play) or conservatively, meaning keep the play in front of you at all times to prevent a bigger play.

Usually corners who play conservatively and play well are the cornerbacks with great adjustment and make-up speed, with that good burst for ensuring the big play doesn't get started. Reacting--again, to the point of almost being proactive--with smart decisions is key. A great example of this is Ronde Barber.

Corners who play aggressively and play well generally are the guys with size and physicality to their game, able to out-muscle at the line and disrupt plays early enough to put themselves in a better position to make a catch than the receiver is. However, they still need to maintain some strong form of a short burst and good general speed for keeping track of and biting on any read they make as soon as they make it. A great example of this is Al Harris.

Then there are the cornerbacks who do both pretty well, and often are allowed to play freely and read, react and be conservative or aggressive based on what they see. You generally need to be a very well rounded cornerback (in terms of skill sets and "immeasurables") to do this. A good example of this style of play is Marcus Trufant.

Champ Bailey plays the ball as well as any corner in the NFL.
Zone and man coverages

As with conservative and aggressive styles of reading and reacting, a cornerback has to be able to play to the defensive preference of the coach in terms of coverage scheme. As was the case with zone-blocking and man-blocking, all teams use both, but tend to favor one of the other. The difference is, man and zone coverages can be combined each play, with, for instance, the slot and X-receiver being manned, while the other cornerbacks are playing zone coverages.

As a result, cornerbacks need to be able to do both. Still, some corners tend to fit the mold of one type of coverage corner over the other, and play that coverage better.

Zone-coverage is when the corners cover a portion of the field. This area is assigned by the play, and can be nearly anywhere on the field depending on the play design. It is intended to confuse the offense, forcing the quarterback to find an open area and sometimes delay his throw until his target hits an open area of the field, or "hole in the zone."

There will always be a gap or hole in the coverage with zone assignments, it's just a matter of finding them and having the right route to hit them, which in turn gives the time advantage to the pass rush. Receivers and offenses can counter this with option routes and post-snap route adjustments that the quarterback and receiver must both read and make in sync--a difficult task.

Cornerbacks that "project" to zone defenses are physical in their style of play and are very good at reading and reacting to the point of proactivity. They don't need to have as much speed so much as a short length burst, and again, I can't stress enough the need to be extremely quick with reactions to play zone well. Asante Samuel is a good example of this type of player.

Man-coverage is when a cornerback is assigned to "shadow" a particular receiver (or in some cases, tight end) and cover them the length of the play in a one-on-one matchup of abilities. One wrong step, one wrong read or one slow step, and the receiver could very well be beating you for six. The positive is just the opposite: good steps, good reads and fast feet can prevent you from having to defend one pass or make one tackle all game. This is the true sign of a great corner.

But as the saying goes, no one stays covered forever. Eventually, especially with the rules favoring the receiver, a quarterback is bound to find a target sometimes. The same as with "holes in the zone", it depends if the breakdown happens before the pass rush gets there. If you haven't caught on, a good pass rush is a corner's best friend.

Cornerbacks who are great in man coverage generally are the faster of the cornerbacks, with great back peddling and the knowledge to combine aggressive and conservative play and use it to their advantage. A great example of this is (homerism or not, it's true!) Terence Newman.

Slot corners

Covering the slot is a tricky ordeal. Some teams prefer, as with their starters, a good man or zone corner for the position. A good slot corner generally is a well-rounded corner, able to do both at any given time, and they need to be able to play the run working in that position.

Other than that, there really is no difference between a slot corner and a starter except where they play in the defense. And none of that truly is a difference at all.

Summarized

While it comes down to scheme and preference, cornerbacks, especially the good ones, need to be able to do it all. Any lack of ability can get exploited by a good offense, and often if you have one really good corner, it can force more efforts to the other side of the field, making that corner look worse than he is.

It's an important and unique position. The best corners often don't get noticed for a while because they are quiet in terms of playmaking, keeping quarterbacks throwing the other way. The worst corners can make a play at any time if they study enough film and slowly become effective for a defense, even as a fourth man on the depth chart.

As with many positions, knowledge for the game can triumph over ability.