This position needs so little introduction -- when you've got QBs slinging the ball 50 times a game and 22 celebration dances after the catch, you can't miss these guys. Part thoroughbred, part American Idol contestant and part Spiderman, the receiver is pretty much the apex of grace, power, and ego-driven showmanship in our species.

Most receivers share these traits, but not all of them are created equal in their skill sets. Let's talk about the different 'positions' within the position. Contrary to sports-talk radio, the differentiation within the WR spot is not having a "number one" receiver (i.e. favorite or most productive), a "number two" receiver, and so on. The basic three-receiver alignment is an 'X' (formation's left), and a 'Y' and 'Z' (formation's right). In more traditional personnel groupings, the 'Y' is the TE; in the event that there is no TE, the 'Y' is the slot receiver. If a fourth receiver is added, that is the 'F' (sometimes called a 'W' or an 'A'). In scouting and recruiting, here are the differences.

The 'X' or 'Z' receivers are mostly aligned on opposite sides and on the outside of the formations. Not surprisingly, many of the routes designed for these positions work the outside and down the field. Due to the length and difficulty of these throws, receivers help their quarterback by having big targets for him to hit, hence the term, 'target receiver'. Additionally, an 'X' receiver is usually lined up on the line of scrimmage. If a team decides to press your receivers the 'X' has no buffer of space, so he must be able to defeat the press at the line. Depending on the formation, the other receivers may also find themselves in this position, but the 'X' needs to be the most capable. Examples of 'X' receivers are guys like Calvin Johnson, Andre Johnson, Brandon Marshall and Julio Jones, to name a few.

Since the 'Z' receiver is typically lined up off the line of scrimmage, he needs to be a speed guy to utilize his cushion against the defense. He defeats the press or defense with speed. This is usually the position where the 'deep threat' is played and/or athletes capable of running the ball on an end-around -- think of guys like DeSean Jackson, Alshon Jeffrey and Sammy Watkins. So in summation, an ideal 'X' is big and physical and an ideal 'Z' is big-ish and fast.

On the inside with a 'Y' receiver and/or an 'F' receiver, the receiver needs a different skill set. The routes that emanate from the slot develop quickly and typically work short areas, whether they are in- or out-breaking. This position needs to be quicker than fast and excel at explosive, quick routes. Guys like Wes Welker and Randall Cobb are great pro examples of these tools.

When it comes to recruiting, these athletes are the God-given natural movers who play a highly visible position. They are the prime cuts, and as such they hit the radar faster than almost any other position, save for QB. You'll find many FBS schools offering receivers even before their junior season is complete.

Measurables: This is the toy aisle of scouting. Amongst all the positions, receivers' measurables are the most provocative. Tall, fast, and springy is always in season. For outside receivers, evaluators are looking for 6-foot plus. In a perfect world, the 'X' is anywhere from 6-foot-2 to 6-foot-5 and a broad-shouldered son-of-a-gun who looks like he can add up to 20 pounds. Recruit what he will be, not what he is!

Inside receivers can really be any height, but shorter limbs and narrower hips almost always have the advantage of delivering highly coordinated, explosive movements. Tested speed should be sub 4.6, depending on the size combination. You'd love for a 'Z' to be in the 4.4s and for nside guys to be in the 1.6s and 1.7s in the 10-yard split. Again, I'll note that handheld times are about .2-.3 slower than the electronic times seen at the NFL combine. A high school 4.5 is really much closer to a 4.75.

Outside of the height-speed combination, vertical and broad jumps are also key barometers of functional athleticism for a receiver. Like a RB, broad jumps should register over nine feet for a WR, while the vertical should come in above 30 inches. If a receiver checks these boxes, then go back to the film to see if it translates.

Stem/Route: From the snap of the ball, a receiver should explode out of the stance with little wasted movement. An example of wasted movement would be the receiver rocking his weight back, shuffling his feet, or popping up before moving forward. These are things that happen to everyone; having a dominant side lends itself to subconsciously favoring natural movements, such as a right-hander wanting to spring off of his left foot. The good thing here is that this can be coached and drilled out of someone. So wasted movement off the snap is by no means a deal breaker, but it can help delineate the difference between being 'raw' and 'polished'.

If the receiver gets pressed at the line of scrimmage, he should be able to show at least one consistent press-beating move. Big guys like Calvin Johnson aim to swat away the defenders hands, turning their torso, and ripping through. On the opposite end of the specimen spectrum, a receiver can defeat the press purely through speed or stutter-stepping. Whatever type of receiver is being recruited, they need to have at least one 'go-to'. However they defeat the initial press, the next goal of a receiver is to "stack" the defensive back. Stacking is simply passing by the defender and having him trail. Getting into the route stem against press coverage, a good receiver prospect should be able to beat the press and stack within five yards.

At the top of the route stem, a quality prospect should be able to get on his toes to break with precision and maximum efficiency. Players who pound the turf flat-footed and throttle down to break might as well have shown the DBs a diagram of their route. More polished receivers will show proficiency at using some stutter-steps, mixing speeds and looking-off the coverage with their eyes, head fakes, body lean and so much more. Route-running is such a craft; take a look at this excellent clip to get a feel for what it looks like at the highest levels. The combination of moves on some of those routes would shame Mortal Kombat.

Catch/Run: What does it mean to have ball skills? This is a commonly applied phrase to a receiver, and it fits into the pantheon of dull sounding scouting expressions. Essentially it means to excel at making the catch, all kinds of catches, look natural and easy.

First, a WR should catch almost every type of throw with his hands extended from the body. The ball should not be trapped against the body and cradled like an infant -- this is lazy and prone to having the ball bounce wildly. To take it further, when catching with the hands, a receiver should really be catching with his fingertips, not his palms. The fingers should naturally absorb the velocity of the throw before providing 10 pressure points to secure it. A rigid palm is another opportunity for the ball to bounce off. Ball skills also means having the intrinsic understanding of when to come back to the ball and when to 'high point', or out-jump the opponent, for the throw.

With the ball successfully secured, what does a receiver do with it? Styles are different: some are natural playmakers in open space, while some lack the field vision and creative instincts to do much more than mash the turbo button getting to the sideline. These are all parts that make up the whole.

If you find a physical receiver who gets open and catches everything, it might have a net positive result compared to an electrifying runner with mediocre ball skills. One gets on the Top 10 plays, but the other is more likely to win games.

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