You don't need numbers to tell that the Cowboys' offensive line played poorly this year. Outside of a handful of games, it was obvious to anyone who watched the team in 2012 that the offensive line struggled, and with the current rotation, it's unlikely that Dallas would improve much offensively in 2013.
While stats aren't a prerequisite for understanding that Dallas has a below-average offensive line, they can be used to determine exactly how much the line set the offense back this season. More important, the right sorts of stats can provide us with an idea of just how much the 'Boys need to improve up front and how to proceed in 2013.
In this particular post, I'll compare the pass protection of the Cowboys' offensive line this year to that of the top players from around the league. First, let's take a look at the number of pressures (as per Pro Football Focus) and sacks yielded by the Cowboys' primary five starting offensive linemen in 2012.
LT Tyron Smith: 37 pressures (6.0 percent of pass snaps), 3 sacks (0.49 percent)
LG Nate Livings: 14 pressures (1.9 percent), 5 sacks (0.68 percent)
C Ryan Cook: 12 pressures (2.2 percent), 2 sacks (0.37 percent)
RG Mackenzy Bernadeau: 24 pressures (3.3 percent), 6 sacks (0.81 percent)
RT Doug Free: 42 pressures (6.2 percent), 7 sacks (1.00 percent)
You can see that Smith and Free allowed the most pressure this year, although that's not really a surprise because of the positions they play. The offensive tackles on almost every team allow more pressure than the interior linemen. In order to determine how effectively each lineman really played, we need to compare each to others around the league at their respective positions.
Below, I've created a numerical value for each lineman that rates their play respective to others in the NFL. The number is representative of the relationship between the pressures/sacks allowed by each player and the same stats for the top-10 players in the NFL at his position. A value of 1.0 means the lineman's pass protection was on par with other top-10 players at his position, while a value of 2.0 means he allowed twice as many pressures (or sacks) as the other top-tier players. Thus, the lower the number, the better.
LT Tyron Smith: 2.00 pressure rating, 0.74 sack rating = 2.74 pass protection rating
LG Nate Livings: 0.90 pressure rating, 2.13 sack rating = 3.03 pass protection rating
C Ryan Cook: 1.38 pressure rating, 1.16 sack rating = 2.54 pass protection rating
RG Mackenzy Bernadeau: 1.57 pressure rating, 2.53 sack rating = 4.10 pass protection rating
RT Doug Free: 1.63 pressure rating, 1.27 sack rating = 2.90 pass protection rating
Remember, a lower value is better. In comparison to others around the league, the Cowboys' worst offensive lineman in 2012 (in terms of pass protection) was Bernadeau, and it wasn't even really close. Bernadeau allowed 18 fewer pressures and one fewer sack than Free, but he also played the far less demanding right guard position. The average top-10 guard in 2012 yielded only 13 pressures and just two sacks, putting Bernadeau's numbers in perspective.
Meanwhile, it's rather surprising to see Cook ranked at the top of the list respective to his peers. Cook didn't seem to play too poorly this season, but based solely on watching the games, I would have placed both Smith and Livings ahead of him. Still, he allowed only 12 total pressures and two sacks with a significant number of snaps.
Looking ahead to 2013, it's clear that changes are on the horizon for this unit. Remember, an average top-10 player at his position would have a pass protection rating right around 2.00 using this system, meaning none of the Cowboys' linemen protected their quarterback even close to as well as a top-10 player. That's particularly evident when you consider that Tony Romo's elusiveness likely helped the players' sack numbers.
Outside of Smith, it's fair to wonder whether any of the other linemen will be in Dallas next season. It might be impractical to replace four starters, but it's also difficult to justify a return for most of these players. My hunch is that the left side of the line, Smith and Livings, will remain intact. Cook will be replaced by a healthy Phil Costa, leaving the right side of the line to replace. If the Cowboys can somehow find two effective starters via free agency and the draft, it's likely that you'll see Romo with a whole lot more time to throw in 2013.