Good Offensive Tackles Are Worth As Much As a Starting Quarterback

I wanted to break through all the hype that surrounds offensive linemen, though, and try to ask some questions that put some of the vague notions of how important they are into context. Today, I’ll start with an attempt to try to answer the burning offseason question, “how many points is a good offensive tackle worth?”

To do this, I looked at all offensive linemen since 1978 who made at least 1 pro bowl and started 80 or more games in their careers, and then found any season in which that player played in fewer than 10 games before age 34, after starting more than that amount the previous year at the same position. I then compared the team performance in things like points, yards per attempt, sack rate, and rushing yards per carry. As it turns out, we don’t have very many cases that allow us to look at this (19 players). If I had reliable game by game data for offensive linemen participation, I could broaden the study, but for now, I can’t tell which games a lineman missed, like I can with a quarterback or running back. My goal in setting this up the way I did was to find pretty good tackles and try to see if there were any differences the following year when they missed a large chunk of the season.

Our 19 offensive tackles averaged 15.1 games the year before the injury, and only 6.3 games played during the injury season. That’s a difference of 8.8 games played, or over half a season.

POINTS PER GAME

The teams in question scored, on average, 25.7 fewer points in the injury season for their star offensive tackle. That’s an average of 2.9 points per game. Well, except it really isn’t. The dropout was likely greater than that, because remember, our injured tackles did play 6.3 games on average during that dropoff season; if we want to get a rough estimate of their worth, we need to account for that. Dividing the point dropoff by the games played difference gives us 2.9 points per game dropoff when the star tackle is out.  It’s an apples to oranges comparison (my cutoff of requiring a pro bowl was designed to weed out right tackle types that weren’t considered dominant but started for a while), but in looking at the estimate for starting quarterback worth of 2.3 points, I’m at least in the ball park with this method.

RUSHING YARDS PER CARRY

This was an interesting one. Most star tackles are considered the best pass blockers at their position, but I was still surprised to see no effect on the running game as measured by yards per carry. It may be only 19 players, but it is hundreds of games and thousands of carries for each type of season (before injury vs. injured tackle). The results, taking to the thousandth digit: 4.011 yards per carry in the previous year, and 4.016 yards per carry the year the tackle was injured.

NET YARDS PER ATTEMPT

So if there was no impact on rushing efficiency, but the points went down, it’s gotta be the passing, right? Net Yards Per Attempt includes the Passing Yards, and also deduct Sack Yards. The Net Yards per Pass did drop, from 6.33 in the previous year to 5.94 in the injury year. Again, just like we did with wins, we have to adjust for the fact that the linemen did play some during that injury year. The likely effect on a per game basis when playing versus when out with an injury was somewhere between 0.7 to 0.8 Net Yards per Attempt dropoff. That’s fairly large–it would be like going from Chad Henne’s numbers in 2010 to Matt Schaub’s, or from Matt Schaub’s to Aaron Rodgers.

So, the next question is how is that distributed? The sack rate did increase with the tackle injured, from 6.79% on average to 7.28% on average. Adjusting for tackle games played, that per game increase was on the order of about a 0.9% increase in sack rate per game. That would be about 5 more sacks over the course of a full season without a star tackle–a definite increase but also far lower than what I think most people would think. The sack rate portion of that net yards per attempt figure accounts for about 0.1 to 0.15 of the dropoff; the rest is good old yards per attempt when a pass leaves the QB’s hands. I’ve said that I think the quarterback is more involved in sack rate than people think, and the offensive line is far more involved in yards per pass attempt than they get credit for. The loss of a lineman had some impact on sack rate, but a bigger impact on the yards per attempt. The quarterback may still get rid of it, he just has to do it sooner.

[photo via Getty]