After seeing a reasonably good (if not awe-inspiring) start to the Aaron Rodgers era, it's interesting to note this little football factoid on the Freakanomics blog: the highest-paid players in the NFL are, of course quarterbacks. So who are the second highest-paid players? You might think it was a running back -- running backs take a lot of physical abuse, are frequently injured, score a disproportionate number of touchdowns compared to other positions, are responsible for carrying the team down the field, and drawing defenders away from the prima donna recievers. Particularly because they play such a critical role in making the offense happen, and because they have such a high propensity for injury, you'd think that they would demand high pay.
In fact, with the exception of one or two elite RB's, RB's are actually among the lowest-paid players on an "average" NFL team, coming in ahead only of place kickers and punters. I presume this is because while demand pressure for good running backs is certainly there, the supply of available candidates is high.
No, the second highest-paid players are left tackles. Why? They key is found in the fact that on teams who have starting quarterbacks who are left-handed, right tackles are the second-highest paid players. This player's job is to protect the quarterback's blind side so he doesn't get sacked and potentially injured. Now this makes sense. Teams invest huge amounts of money in quarterbacks because not many players have both the physical ability to heave the ball where it needs to be and the mental ability to read the field and see the tactical opportunities opening and closing before him in real time. But that sort of person tends to be, well, fragile. And so the very best linemen -- the strongest, smartest, and fastest players available -- get diverted to the task of protecting those delicate and easily-injured quarterbacks.
What's not so easy to understand is, if there are a bunch of potential running backs out there, why aren't there a bunch of potential left (and right) tackles? The importance of good players in this position is obvious, but is supply of people who have the necessary combination of size, strength, speed, and instinct really that rare in the world of the NFL? It must be, though, because otherwise left tackles would be paid salaries closer to the league minimum.