It's easy for most people to evaluate quarterbacks, receivers, running backs and even many defensive positions for which ready stats are available every which way you look. Such evaluations may not be perfect, but there are hard numbers people can lean on to back them up.
The offensive line is different.
There are no stats readily available, and the most some people lean on is the number of sacks given up over the course of the season. There is certainly some merit to such numbers, and usually those giving up fewer sacks have had better overall seasons across the board.
But offensive linemen these days play well over 1,000 snaps in a season—you can't separate a bad one from a good one on the basis of five snaps: giving up no sacks in a season versus a year giving up five.
The truth of the matter is that in order to evaluate offensive linemen, you need to watch them play.
And only by comparing how they do can you hope to have a realistic idea of how they performed.
That, though, has a couple of problems.
Firstly, it's tough to watch linemen live. It sounds silly, but it's true. You naturally want to follow the ball and see what happens on the play, and it takes real work to keep watching the same battle in the trenches in a live game. Your best bet is to evaluate after the fact.
Secondly, people tend to work from a mental highlight reel when evaluating line play. You remember the splash plays—good and bad—or things pointed out to you by analysts during games, and you throw out the rest.
If those highlight plays were more good than bad, you conclude that a given player probably had a pretty good game.
But it's the 50 other snaps that usually determine more accurately how he actually performed.
Was he successfully turning his defender and sealing him away from the run? Did he get to the second level and obstruct linebackers, or was he constantly on his back foot, allowing the hole to be squeezed and the defense to have the upper hand?
Those are the plays that decide games over 60 minutes, but they may not be noticed unless you're watching and recording what you see on every snap.
I'm fortunate enough (or unfortunate enough, depending on how you look at it) to get paid to do that for a living, and over the past few seasons I have watched more tape on offensive lineman than most people on the planet. While the mainstream media continues to wax lyrical about the same few overrated faces on the offensive line, I'm going to introduce to you the All-Underrated Offensive Line.
Some of these players you will know well, some you will see purely as journeymen, some as nothing better than average.
But all have been very good players, and all remain extremely underrated.