Line of scrimmage key to QB play, winning

Total QBR is often used to evaluate the best quarterbacks, but it does more than that, shedding insight on how teams are winning. QBR accounts for sacks and scrambles along with when the quarterback throws the ball, making it correlate strongly to winning.

By charting the pressure quarterbacks face, how much time they have to throw, and how many rushers were sent, we also have the ability to understand the line of scrimmage. In combination with QBR, we can then tell a story about how the line of scrimmage relates to winning.

Tom Brady is statistically one of the best quarterbacks in the league, with the second-best Total QBR of 76.6. But how much of Brady’s success is due to having a scheme and offensive line combination that is superior to other teams?

If he had to face the pass pressure that Jay Cutler faces in Chicago, we estimate that Brady’s QBR would decline to 62.5 and the Patriots would lose about 19 points as a result.

Matt Hasselbeck

Hasselbeck has the fourth-best Total QBR this season (73.1), after posting a 45.4 in 2010. One reason for his improvement is that he has been pressured the least of any quarterback and has done well in these situations.

Matt HasselbeckHasselbeckHe has a total QBR of 84.5 when not under pressure, compared to the league average of 73. A big part of his success is a scheme that gets the ball out of Hasselbeck’s hand quickly. The Titans take 2.36 seconds to attempt a pass, one of the best marks in the league.

Ryan Fitzpatrick

The team that takes the shortest amount of time to throw is the Buffalo Bills. Fitzpatrick, also a top-10 quarterback according to Total QBR, has to get the ball out so quickly because Buffalo’s offensive line is the second-worst in the league at allowing pass pressure within three seconds in the pocket.

Tim Tebow

Tebow will be the Denver Broncos' starting quarterback for at least one more week, despite his league-worst QBR of 12.8. Tebow has been pressured on 39 percent of his action plays, the highest rate among regular starters, and hasn’t done well in those situations, with a QBR of just 7.6.

Tim TebowTebowThe problem does not seem to be with his offensive line, as the Broncos are fifth-best in the NFL at allowing time in the pocket without pressure. The Broncos do take the second-longest in the league to throw the ball, which is partly a result of the receiver not getting open. But it took Kyle Orton 2.60 seconds to get a throw away, while it takes Tebow a league-high 3.64 seconds.

Tebow’s QBR when not under pressure is just 18.9. The other quarterbacks with QBR values under 50 when not pressured are Kyle Boller, Luke McCown, Kerry Collins, Blaine Gabbert, A.J. Feeley, Donovan McNabb, and Charlie Whitehurst. Every one of these guys has either lost their starting job or filled in for the starter due to injury or them losing their job.

For exclusive video, stories and blogs about quarterbacks from every level of competition, check out ESPN's "Year of the Quarterback" page.