Loaded box vaults Smith to QBR lead

AP Photo/Tony Avelar

Alex Smith is leading the league in Total QBR after Week 5.At the end of Week 5, Alex Smith is the leader in Total QBR. Let me say that again for San Francisco 49ers fans who have endured some tough quarterback play in recent seasons; Alex Smith is the most efficient quarterback in the league through five games.

Before this season, no 49ers quarterback had led the league in QBR at the end of any week in the QBR era (since 2008).

How is he doing it?

Usually a good QBR can be attributed to a few key factors, two of which are performing well on third downs and when the game is late and close. Smith, however, is actually not performing that well in either situation.

On third downs he has a 37.4 QBR, 20th-best among the 33 qualified quarterbacks. In clutch situations –- defined as the fourth quarter or overtime with the game within eight points –- he isn’t much better, ranking 15th in QBR among the 29 quarterbacks with at least 10 action plays.

So it’s clearly not third downs and it’s not performing well in the clutch. For Smith it’s actually what he’s doing on the early downs while the defense is crowding the line to stop the 49ers running backs.

Alex Smith on 1st and 2nd Down
7+ Defenders in the Box

He is torching defenses on first and second downs with at least seven defenders in the box, posting a 96.3 QBR -– three points better than any other quarterback. This is a marked improvement for Smith, who was not able to take advantage of run-preventing defenses in the past.

A lot of his success on these plays has come by throwing the ball over the top of aggressive defenses. On throws at least 15 yards downfield in these situations, Smith is 10-for-16 with two touchdowns and no interceptions and is one of three QBs with a 100.0 QBR.

This has led to increased effectiveness for Frank Gore and the San Francisco running game as well. From 2009 to 2011, the 49ers averaged 4.3 yards per rush while attaining a first down on 18 percent of rushes on first or second down with at least seven defenders in the box.

Those were roughly league average numbers.

Most Yards Total Offense
49ers History

This season, the 49ers are averaging 6.1 yards per rush and getting a first down on 30 percent of rushes in these situations. Against the Buffalo Bills on Sunday, the numbers increased to 8.2 yards per rush with 37 percent gaining enough for a first down.

It’s not often that a quarterback can be so average in higher leverage situations and have such a good QBR.

But if Alex Smith can continue to take advantage of defenses not respecting him on early downs, he and the 49ers should continue to be one of the best offenses in the league.