How Much Influence Does an Offensive Line Have on Quarterback Success?

Tyson Langland@TysonNFLNFC West Lead WriterMay 22, 2013

DENVER, CO - DECEMBER 2:  Quarterback Peyton Manning #18 of the Denver Broncos adjusts the play at the line of scrimmage during a game against the Tampa Bay Buccaneers at Sports Authority Field Field at Mile High on December 2, 2012 in Denver, Colorado. (Photo by Dustin Bradford/Getty Images)
Dustin Bradford/Getty Images

Success at the quarterback position in the NFL is not only predicated on the individual success of a signal-caller, but it is predicated on the success of his supporting cast. Whether that is his backfield, wide receiving corp. or offensive line, everyone has a hand in the accomplishments of a team’s offense.

Moreover, the same can be said about a team’s offensive failures. On any given play, there could be an individual who misses a blocking assignment, fumbles the football, drops a pass or simply runs the wrong route. All of these misfortunes directly or indirectly affect the quarterback.

However, no offensive position affects a quarterback’s play more then the offensive line. Over the course of a game, offensive linemen are asked to keep the quarterback upright by giving him adequate time to throw the ball.

When given adequate time to throw the ball, quarterbacks have a higher probability of finding the open receiver. This, in turn, leads to more passing yards, completions, touchdowns and overall offensive success.

With the help of Pro Football Focus’ (subscription required) in-depth analytics database, we are going to measure how much influence the offensive line has on quarterback success.

In the chart above, players are sorted from best to worst based on their Pro Football Focus passing grade. The 49ers, Titans, Jaguars, Chiefs, Cardinals and Eagles have combined quarterback grades because those six teams featured two quarterbacks who played more than 25 percent of their team's offensive snaps.

Aside from being sorted from best to worst, the list is equally separated into two groups. The top group features the 16 best quarterbacks in the NFL, and the bottom group features the 16 worst quarterbacks in the NFL.

When one takes the time to analyze the chart, it’s apparent that organizations suffer when they have to use two different quarterbacks. Jacksonville, Kansas City, Arizona and Philadelphia all finished with negative PFF passing grades. San Francisco and Tennessee were the two lone multi-quarterback teams that finished with positive PFF passing grades.

The 49ers were put in a unique situation when Alex Smith suffered a concussion against the St. Louis Rams, while the Titans had Matt Hasselbeck to fall back on after Jake Locker exited Tennessee’s Week 4 contest against the Houston Texans with a left shoulder injury.

After collecting the data and running the numbers, it also became evident that even the slightest of differences in offensive play affected a quarterback’s effectiveness over the course of a 16-game season.

For example, take a look at the calculated averages of the league's top quarterbacks and their offensive lines. The average PFF passing grade from Peyton Manning to Jay Cutler was a plus-24.8, while the average PFF passing grade from Joe Flacco to Brandon Weeden was a minus-9.6.

Moreover, the top 16 quarterbacks, on average, were sacked less, hit less and pressured less than the bottom 16 quarterbacks. Thanks in large part to the Cleveland Browns; the cellar dwellers did surpass the top-notch talent in one category (offensive line hurries allowed). 

Yet, a year's worth of data doesn’t exactly tell the whole story. We need to go back in time and examine the success of past Super Bowl champions. In 2008, Pro Football Focus (subscription required) proclaimed that the Pittsburgh Steelers were one of the five worst pass-blocking offensive lines in all of football.

That notion didn’t seem to bother Ben Roethlisberger and his offensive line. They rolled through the playoffs and beat the Arizona Cardinals in the Super Bowl. Surely it was a fluke that they won the Super Bowl with such porous offensive line play, right?

The 2011 New York Giants would attest that it was no fluke. Per PFF (subscription required), the Giants had the worst offensive line in the NFL at the end of the 2011 season. There wasn’t a single offensive line that surrendered more quarterback pressures that year.

So, what did the 2008 Pittsburgh Steelers and the 2011 New York Giants have in common? Both teams had quarterbacks who managed to overcome subpar offensive line play all throughout the playoffs. Eli Manning and Roethlisberger combined for 1,911 yards passing, 12 touchdowns and two interceptions amidst bad offensive line performances in the playoffs.

Even though strong quarterback play can often outshine bad offensive line play, Manning and Roethlisberger are seemingly exceptions to the rule in years past.

In 2009, the New Orleans Saints had the 11th best pass-blocking offensive line in the NFL. Additionally, the Green Bay Packers had the third best pass-blocking offensive line in 2010, while the Baltimore Ravens had the 17th best pass-blocking offensive line in 2012.

This just goes to show that advanced data and analytics are great tools that help us understand the story, yet they are only a small piece of the puzzle. In terms of quarterback success, offensive line play may have the greatest impact on the position, but there are other factors that should be factored into the equation as well. 

Accuracy, arm strength, toughness, pocket presence and awareness are a few of that attributes that help define a quarterback. A top-notch offensive line can only control what they do in pass protection; they can’t help a quarterback with his accuracy, arm strength, toughness, pocket presence or awareness.

Despite the fact that numbers from the 2012 season support the notion that strong offensive line play directly correlates with strong quarterback play, it’s simply unquantifiable based on numbers alone. Sure, it doesn’t hurt to have a good offensive line, but in the end the NFL is still a crapshoot.

Rather than a team’s offensive line, a handful of plays away from the line of scrimmage seemingly have a higher probability of impacting the annual success of a quarterback. Football is the ultimate team sport, which in turn makes each position equally valuable in terms of offensive and defensive success.