[scott_s]

That was my thought, too. I'm guessing the group on the far right are the linemen, the group on the far left are the receivers, and the middle group are those that cover the receivers.

What I find most interesting is that there's a clear gulf between the (probable) linemen on the far right and the others. That middle ground is probably not best suited for any role - if you're chasing the receivers, you're going to be too slow, and if you're trying to protect or attack the line, you're going to be too small.

[jackschultz]

The group on the far left would be the defensive backs actually. That position is best suited for the little and quick guys. While receivers can, and are small (think a Wes Welker type), receivers are also enormous (Calvin Johnson). If a corner were the size of Johnson, for example, the team would put him in as a receiver since that's more valuable.

Take a look at this reddit post with more detailed information that's position based. http://www.reddit.com/r/dataisbeautiful/comments/1oh47i/heig...

[dpeck]

Middle group is likely to be primarily made up of linebackers, running backs, with a few of the larger tight ends there as well.

These players, while having some responsibility in the passing game are primarily involved in either running the ball, or defending against the run. And having a bit more mass there is very beneficial, but they still need to be able to have the speed to be able to work horizontal across the field and sometimes be quite a ways away from the line of scrimmage by the end of the play.

[maxerickson]

incision's link, in a top level comment, has a plot that distinguishes positions. (Modern) Tight ends are heavier than linebackers, then quarterbacks, then running backs.

[sheri]

The middle group as mentioned is a mix of linebackers, tight-ends and also running backs. > That middle ground is probably not best suited for any role Modern NFL is very specialized. You have linebackers of various sizes who are used in situational conditions (passing vs running downs), and also vary in size/height based on the defensive scheme. e.g. A linebacker in a Cover-2 based defense is probably lighter/faster vs a larger linebacker used in a 3-4 defense.

[chiph]

William "The Fridge" Perry was probably the inspiration for the absolutely huge linesmen of today. That separation started a little bit after his seasons with The Bears.

http://en.wikipedia.org/wiki/William_Perry_(American_footbal...

[MisterBastahrd]

Probably not as much as you think, because he really wasn't that good of a football player and made his name as a situational fullback. The Cowboys offensive lines of the early 90s are probably the blueprint for the current NFL offensive lines. Those guys were freaking enormous compared to the average line, and it's the main reason why Emmitt Smith is a household name.

[chiph]

No question those guys were bigger. Mark Tuinei was 6'5", 310 lbs. Larry Allen was (at the time) 6'3" 325 lbs.

Tuinei was a contemporary with Perry in the mid-late 80's, but Allen wasn't drafted until the mid-90's.

I still say that Perry was an inspiration. :)

edit Fix team name. Ooops.

[Steko]

The Cowboys themselves were modeled after the Hogs and Giants offensive lines of the 80's. The competing archtype in the late 80's early 90's was the lighter, more agile offensive lines of the 49ers.

[MisterBastahrd]

I'd agree with that. The 49ers of that era were able to benefit from a lack of a salary cap. They were stacked across the board. It was the place you went when you were an aging star who wanted to win a ring. They wanted those more nimble guys because of the crazy pass rush of the other teams in their division and conference.