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The 2009 Cowboys O-Line: Inside the Run Blocking Game (Part I)

Your offensive line may be the most important part of your football team. The gridiron battle is won or lost at the line of scrimmage, and the offensive line is the lynch pin, literally underpinning the success of a team's offense. In the world of fantasy football, we cheer for heroes such as Peyton Manning, Chris Johnson and Andre Johnson to fill the stat sheets and lead our teams to victories. But even the best players can struggle to produce without effective pass protection or holes to run through. Yet offensive linemen rarely get the adulation accorded to quarterbacks, running backs and wide receivers. They get noticed only when they make mistakes, but they're the key to moving the ball. Their battles are constant, and their victories more subtle, their stats invisible.

How do you judge the performance of an offensive line?

You can always do an eye-test and come away with such profound insights as "Wow, he has so many penalties, he must be really bad" (Helloooo Flozell Adams) or "Hey, they’re all over thirty, they must be old, slow and they tire easily at the end of the half/game/season" (Helloooo everybody).

You’ve heard all about this particular players’ slow feet, that players’ high center of gravity and yet another players’ bench pressing prowess. You may have tried following a debate on the finer points of the three point stance and probably gave up in exasperation once the discussion moved to proper hand placement technique and arm length.

But what does all that really tell you?

Evaluating the performance of an offensive line is not an easy undertaking, simply because success is often only measured by what didn't happen: the quarterback was not sacked and the running back was not stuffed in the backfield. There aren’t a lot of stats out there that will help you tell a good offensive line from a bad one.

But there is hope: The statistical cavalry in the form of has developed a couple of advanced metrics that evaluate offensive line performance based on a variety of factors. Since the goal of the offensive line in the running game is to give running backs the time and space to produce their numbers, our break-down focuses on four statistical categories – Line Yards, Power Success, Open Field Yards and Stuffs. Let’s see how the Cowboys offensive line fared in 2009 according to the FO metrics.

FootballOutsiders have developed their own metrics and their own terminology, and I’ve used their definitions to preface each of the statistical categories we’ll walk through below.

Adjusted Line Yards:

Based on regression analysis, the Adjusted Line Yards formula takes all running back carries and assigns responsibility to the offensive line based on the following percentages:

Losses: 120% value
0-4 Yards: 100% value
5-10 Yards: 50% value
11+ Yards: 0% value

These numbers are then adjusted based on down, distance, situation, opponent, and the difference in rushing average between shotgun compared to standard formations. Finally, we normalize the numbers so that the league average for Adjusted Line Yards per carry is the same as the league average for RB yards per carry [which is 4.29 yards].

What these numbers mean is that the offensive line is penalized for losses (a run for -5 yards is credited with -6 yards) and gets progressively less credit for a long run: The first four yards of a run are fully credited, the next six yards (the running back hits the second level between 5 and 10 yards out ) are only credited with half the yardage, for all yardage beyond the 10 yard line (the running back is now in the open field) the offensive line doesn’t get any credit whatsoever. This makes sense because you don’t often see offensive linemen blocking ten yards down the field for a running back – people are still raving about Doug Free's downfield block on Felix Jones' touchdown run against the Eagles exactly because it was so rare to see an offensive lineman in that territory.

Using Adjusted Line Yards, this is how the Cowboys offensive line performed in 2009:

Rank Adj. Line Yards RB Yards NFL Avg
2009 3 4.47 4.99 4.29

This may come as a bit of a shock to those of us whose last Cowboys memory is of the Vikings game, but the Cowboys offensive line ranked third in the NFL in terms of Adjusted Line Yards last season.

But … but … but, aren’t they a bunch of over-the-hill has-beens? Well, it is true that the Cowboys offensive line has more NFL starts to their credit than any other offensive line, but like I say to those 20-somethings populating my favorite watering holes, "Age is all in the mind when youthful in spirit, honey. And think of all the experience …."

Think of the Adjusted Line yards as follows: On average, the Cowboys offensive line cleared the path for 4.47 yards per run for their running backs. Only the Dolphins (4.50) and the Saints (4.48) were better, by the narrowest of margins.

The next column in the table above are running back yards. FO define these as:

Yards per carry by that team's running backs, according to standard NFL numbers.

The Cowboys’ running backs gained 4.99 yards in running back yards, second only to the Chris Johnson-led Titans with 5.29. What the 4.99 means is that Marion Barber, Felix Jones and Tashard Choice combined to gain 0.52 yards on average more than the offensive line provided.

And this is where it gets interesting. A great offensive line will make even an average running back look good if you only look at traditional stats like total yards and YPC. The Running Back Yards minus Adjusted Line Yards provide a measure of how good a running game a team has, by taking away the contribution of an offensive line, be it good or bad. The table below does just that for the top six and bottom six teams last year.

Running Back Yards minus Adjusted Line Yards

Top six Teams
Bottom six Teams
Rank Team RBY-ALY Rank Team RBY-ALY
1 TEN 1.28 27 NE -0.10
2 CAR 0.90 28 GB -0.12
3 KC 0.74 29 IND -0.13
4 SF 0.72 30 WAS -0.20
5 BAL 0.55 31 HOU -0.37
6 DAL 0.52 32 SD -0.48

So what does this mean? Take the Titans and the mighty Chris Johnson (and the other guys who occasionally carried the ball for the Titans). Their running game averaged 1.28 yards per carry more than their offensive line provided for. Put differently: if Chris Johnson were to run behind the Miami, New Orleans or Dallas offensive lines, he might come close to 6 yards per carry. As a Dallas fan, wouldn’t that be something to salivate over? A big play running back with monster YPC stats! But wait … don’t we already have one of those?

Not one, but two! Active NFL YPC leaders, min 100 ATT.

Rank Player From To Team ATT Yards YPC
1 Felix Jones 08 09 DAL 146 951 6.51
2 Jamaal Charles 08 09 KC 257 1,477 5.75
3 Justin Forsett 08 09 SEA 114 619 5.43
4 Jerious Norwood 06 09 ATL 373 1,987 5.33
5 Chris Johnson 08 09 TEN 609 3,234 5.31
6 Tashard Choice 08 09 DAL 156 821 5.26
7 Ahmad Bradshaw 07 09 NYG 253 1,323 5.23
8 DeAngelo Williams 06 09 CAR 754 3,850 5.11
9 Pierre Thomas 07 09 NO 328 1,670 5.09
10 Shonn Greene 09 09 NYJ 108 540 5.00

And then there are the have-nots of the league, led by the Chargers, whose running backs actually gained less than what the offensive line provided.

Okay, so now that I’ve sung the praises of our much maligned offensive line, I can hear you asking "But what about all those failed short yardage and goal line attempts? And aren’t some of the longer runs by the Cowboys running backs screwing with those averages?" Thank you for that extraordinarily insightful question. On to the next metric.

Power Success

Percentage of runs on third or fourth down, two yards or less to go, that achieved a first down or touchdown. Also includes runs on first-and-goal or second-and-goal from the two-yard line or closer.

If you suffer from depression, have anger management issues or another condition that might lead you to react unfavorably to bad news, you should stop reading now. Go pet a dog or something.

It’s hardly a secret that the Cowboys offensive line struggled, and struggled mightily, with running plays on short yardage situations and goal line attempts. The numbers bear this out: The Cowboys ranked 26th in power success with 58%. Not a big revelation there, but consider that in 2008 and 2007 the Cowboys ranked 15th and 12th respectively, both times with 68%.

Rank Power Success NFL Avg
2009 26 58% 64%

Here’s what’s baffling: compared to 2008 both the offensive line and the running backs were significantly healthier in 2009. Blogger Yoko Romo weighs in on the topic:

Dallas’ best running play, by far, is the draw (Football Outsiders found this when they analyzed our running game late last season). Draws make use of our large, athletic linemen who are more comfortable pass protecting (or pretending to pass protect) than blowing people off of the line. I think our lineman are more "big" than they are "strong". Draws work great on first downs in your own territory when defenses don’t know if you are going to pass or run, consistent with our strength in those areas. In short yardage and goal line, draws aren’t going to fool anybody.

Instead of drafting a big, athletic tackle/guard hybrid that the Cowboys usually seem to covet, we should draft a "mauler" who is more strong than athletic and can knock opponents backwards. Having two guards that are better at pulling than blocking the man in front of them makes it hard to run up the middle.

Between Hudson Houck, Skip Peete and Jason Garrett, fixing the Cowboys’ short yardage woes is something that the Cowboys will have to work on for next season.

10+ Yards or Open Field Yards

Percentage of a team's rushing yards more than 10 yards past the line of scrimmage. Represents yardage not reflected in Adjusted Line Yards stat.

This is fairly straightforward. By the time the running back is ten yards beyond the line of scrimmage, the offensive line have done their job and are already getting back up off the ground and are comparing their tattoos and bicep diameters.

FO are now calling all yardage beyond ten yards ‘Open Field Yards’. If you take Open Field Yards as a percentage of total yards, you get an indicator for ‘big play ability’, or at least ‘break away ability’ of your running game. Remember, the Cowboys coaching staff defines any run of 12 yards or more as an explosive play - and they sure like themselves some explosice plays.

The Cowboys not only rank sixth in the league in open field yards, but they have steadily improved in this category since 2006. If I were Jason Garrett, better yet, if I were Skip Peete, this is one little stat nugget I’d have at the very top of my CV.

Open Field Yards
Rank 10+ Yards in % NFL Avg
2009 6 23% 19%
2008 8 22% 19%
2007 11 20% 18%
2006 20 15% 17%


Percentage of runs where the running back is tackled at or behind the line of scrimmage. Since being stuffed is bad, teams are ranked from stuffed least often (#1) to most often (#32).

Ever watch an offensive lineman after a tackle for a loss? If you look closely you’ll see that most of them are highly concentrated on staring at their shoes. This is because that’s the only way you can try to hide on a football field after you’ve just embarrassed yourself in front of a crowd of 60.000+ and countless more at home in front of the TV. You want your tackles for loss percentage to be low. Your manhood requires it.

The Cowboys rank seventh in this category, and to be honest, I didn’t expect anything else. After all, half of the Dallas offensive line is in a heavy metal band. How more manly can you get?

Rank Stuffed NFL Avg
2009 7 17% 19%

Overall, the offensive line performed remarkably well outside of short yardage situations. In the second installment in this series, we’ll look at how the offensive line performed when running the ball in certain directions, and in the third and final part we’ll look at how well their pass protection held up.


[Hat tip to all the fine folks at for crunching the numbers and to Buc Wild from SBNation’s Buc’Em site for providing the template for this post]

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