Dominant skill position players will only take a team so far if they don't have a good offensive line to buy time for plays to develop.
That's not all, though. A sturdy pass-blocking offensive line can be of great value in the pass-happy NFL, but the best offensive lines are well-rounded and can knock a defensive front off of the ball in the running game, as well.
Thus, we'll look for the lines that aren't dominant in just one area, but that can do the job in different scenarios.
Here we go.
New England Patriots
The Patriots offensive line is consistently among the best units in football at protecting the quarterback.
Tom Brady has enjoyed some of the best football of his career over the past six years, but not without a lot of help from the Patriots offensive line, which has ranked in the top 10 in sack percentage at five percent or less every year since 2009. They gave up a sack on 4.04 percent of dropbacks, the fifth-lowest sack rate in the NFL.
Look at the pocket they gave Brady on this 3rd-and-9 play against the Titans.
It wasn't as though the Titans didn't see a pass coming—Brady was in the shotgun, there was no play action and there were three receivers and a tight end split out wide. Brady has enjoyed a great pocket for much of his career, but pass-blocking is not all they're good at anymore.
In fact, the team's 2,184 rushing yards was its most since 2008 and second-most of the Bill Belichick era. According to Football Outsiders, the Patriots tied the Seahawks for third in adjusted line yards (rushing), where New England has ranked in the top five each year since 2007. In 2012, they had just 18 percent of their runs stuffed for no gain or a loss (10th in the NFL).
The most impressive element of the Patriots offensive line is their continued success despite dramatic change over the years. So many players have been in and out, and the offensive line has never once been considered a weak link on the team. Last season alone, the Patriots fielded an offensive line with movement at four of the five spots.
It's a credit to the coaching of Dante Scarnecchia, who has put his blue-collar fingerprints all over the offensive line year after year. Without him around to help the Patriots get the most out of seventh-round picks and former wrestlers, the offense likely wouldn't be nearly as successful as it's been in recent years.
San Francisco 49ers
A gaudy 8.6 sack percentage was nearly enough to turn me away from the 49ers, but a closer look reveals the offensive line may not be as responsible for that figure as it seems. Among quarterbacks to take at least 25 percent of the team's snaps, Alex Smith and Colin Kaepernick were both among the six highest averages in throwing time. Both were also among the six in the amount of time they had in the pocket before being sacked.
If Kaepernick gets rid of the ball quicker, those numbers could all improve. That being said, Jim Harbaugh is looking to take advantage of Kaepernick's arm; 15.1 percent of his throws traveled 20 yards or more through the air, the seventh-highest average in 2012. Given those facts, the 49ers did their fair share in buying Kaepernick as much time as possible for plays to develop.
Oh, by the way, they're one of the best run-blocking offensive lines in the league.
The 49ers have rushed for over 2,000 yards the past two years, and averaged 5.1 YPA in 2012 (third in the NFL). According to Football Outsiders, they also ranked first in adjusted line yards (4.49) and seventh in runs stuffed for no gain or loss (17 percent).
The line is loaded with three former first-round picks, a big-name free-agent in center Jonathan Goodwin and a diamond-in-the-rough undrafted free agent in guard Alex Boone.
Usually, running backs trend downward at a certain age. Given the heavy load Frank Gore has carried throughout his career, you'd think that time would be coming. Gore has been able to improve on his average YPA each of the past two years thanks in large part to blocks like the ones he got on this play.
Gore rattled off his longest run of the season, a 37-yard scamper, on a simple run between Goodwin and left guard Mike Iupati.
It's easy to gain big yards with an alley this wide to run through.
That's no slouch defensive line they did it to, either. In fact, the 49ers averaged 128.5 rushing yards per game and 5.04 rushing YPA against the Seahawks, significantly higher than their season averages in both categories.
We have yet another well-rounded group in the Seahawks offensive line, despite what the numbers might initially tell you. They allowed quarterback Russell Wilson to be sacked on 7.5 percent of his dropbacks (the 10th highest average in the NFL), and allowed him to be pressured on 39.2 percent of his dropbacks (third highest).
As was the case with the 49ers, a quarterback that holds onto the ball for a long time is more likely to get sacked. Wilson held onto the ball an average of 3.35 seconds in the pocket, the longest of any quarterback in 2012.
Much like the 49ers with Kaepernick, the Seahawks were looking to take advantage of Wilson's arm. The rookie went deep on 16.3 percent of his pass attempts, the second-highest average in the NFL.
Imagine how much Wilson might have been sacked with a lesser offensive line protecting for him, but also imagine how much better the whole offense will be if Wilson improves on his pocket awareness, which is already fairly good.
Just ask running back Marshawn Lynch what it's like running behind this group.
Everything came together on this particular run, a 24-yard touchdown scamper by Skittles against the 49ers. The Seahawks gave San Francisco a taste of its own medicine (no, not that medicine) with a pistol formation stretch run.
Every single Seahawks linemen won their assignment, and Lynch took off through the C-gap practically untouched, until he carried cornerback Tarell Brown into the end zone.
The Seahawks averaged 4.8 YPA rushing (fifth-highest in the NFL) with their offensive line ranking third in Football Outsiders' adjusted line yards, and had the NFL's fewest runs stuffed for no gain or a loss.
The addition of wide receiver Percy Harvin has gained a great deal of attention, but the offensive line has been and will continue to be a big reason for the Seahawks offensive success—figuratively and literally.
Unless otherwise noted, all stats obtained from ProFootballFocus.com, and all quotes obtained firsthand or via team press releases.