Re: Mankins Expendible?
posted at 5/21/2010 7:19 AM EDT
Originally Published: August 6, 2008
Why The Left Tackle Is Overrated
Everyone knows the left tackle is the most important position on the offensive line, right? The stats say no, writes KC Joyner.
Many of you probably are familiar with Michael Lewis' book "The Blind Side." It recounts a young player's struggles to adapt to his new environment. From a football perspective, Lewis paints a compelling picture of how valuable the left tackle is to NFL teams.
As excellent as Lewis' research was, after reading the book, I still had some doubt as to the real value of the left tackle. I understood how much it meant to Bill Walsh to have someone capable of blocking Lawrence Taylor. I also had a better understanding of why left tackles are paid so much. But I still didn't have a good sense of how much more valuable a left tackle is than, say, a right guard.
So, what is the real value of the left tackle? I dedicated the lead chapter of my new book, "Blindsided: Why the Left Tackle is Overrated and Other Contrarian Football Thoughts," to that very subject. In the book, I detailed both run and pass blocking analyses, but for the sake of brevity, I can summarize the run blocking portion by saying the metrics show left tackles by themselves don't have a significant effect on the running game.
That really isn't surprising, and it isn't the reason posited by Lewis as to why left tackles are paid a premium. Their perceived value is in the passing game, so I looked at the effect left tackles have by using pass blocking metrics derived from "Scientific Football 2006." Since I have the updated 2007 pass blocking metrics for "Scientific Football 2008," I thought it would be interesting to pair some of the comparative methods used in "Blindsided" with this past year's totals.
The starting point was looking at how many total sacks each team allowed and how many sacks the left tackle(s) on those teams allowed. Here are the 2007 totals in those categories.
|Rank||Team||Sacks Allowed||Left Tackle Sacks Allowed|
The rank column is important for reasons I will explain in just a moment, so please keep it in the back of your mind.
The next step was to look at the percentage of team sacks each left tackle gave up. The goal was to see which left tackles were weak pass-blockers in comparison with the rest of their team's offensive line.
The interesting part of the review came when I resorted the charts by the left tackle sack percentage but left the original team sack total rankings in place (the rankings I mentioned a couple of lines back). Here's what the chart looks like when resorted.
|Rank||Team||Sacks Allowed||LT Sacks Allowed||LT % Of Total Sacks|
This shows that many teams with bad pass blocking lines have very good left tackles, or they at least have left tackles who give up few sacks relative to the rest of the offensive line. For example: Miami, Baltimore and St. Louis all finished 21st or worst in overall sacks and allowed a combined 129 sacks, yet their left tackles were responsible for only 7.5 of those sacks.
There also is an interesting trend for some of the teams near the bottom of the list. Cincinnati, San Diego and Houston all finished in the top eight in sacks allowed, having given up only 63 sacks among them. That means that in general, their players were good pass-blockers. However, their left tackles struggled mightily, giving up 22 of those 63 sacks.
The conclusion I came to in "Blindsided" is that this occurs because defenses choose the path of shortest distance as often as possible when pass rushing. If the offense has a pass blocking weakness at any of the guard or center positions, the defense's plan always will be to target those players first because that is the quickest route to the quarterback.
That's what happened in the cases of the Dolphins, Ravens and Rams.
When the up-the-middle option is not available because of good interior blocking, defenses then target the next-fastest route, which typically is around the left tackle. The Bengals, Chargers and Texans all had solid blocking up the middle, and that is why their left tackles were tested.
That latter example is the only case in which a really good pass-blocking left tackle helps, but it still doesn't take an elite left tackle to win the Super Bowl. For proof of this, just look at the Giants and their left tackle last year, David Diehl
. He gave up 12.5 sacks, the second-most by any left tackle, and New York still was able to go all the way.
KC Joyner, aka the Football Scientist, is a regular contributor to ESPN Insider. His core coverage metrics for all skill-position players and cornerbacks are available in the ESPN Fantasy Football Magazine. His new book "Blindsided: Why The Left Tackle is Overrated and Other Contrarian Football Thoughts," is available in bookstores and on Amazon.com. For more information, check out KC's Web site, www.thefootballscientist.com.