Closer Look at Sack Stats

A reader named George raises a good question about the sack point I made in a post on Tuesday:

"Don't you think you have to take the Giants game out of that sack stat? I think you can make a case that the protection in the Giants game WAS the problem. If it is 18 sacks in 8.5 games, then the difference isn't nearly as much. So you're getting one more sack per game with Donovan. Sure, he should throw it away more, but the sack is better than the INT."

It's a good point (especially considering this week's opponent), so let's dive into the issue a bit more deeply.  To start, here's a look at the career sack numbers of Donovan McNabb, Jeff Garcia and A.J. Feeley.  The sack "Rate" is simply (sacks) / (pass attempts + sacks).  The "Adj. Rate" is (sacks) / (pass attempts + sacks + rushing attempts) to control for the fact that most quarterback runs are actually scrambles on called passing plays.

As you can see, Donovan has the highest sack rates of the three quarterbacks, as well as the largest spread between the two rates.  Neither observation is that surprising.  McNabb has always taken a lot of sacks, partly because he's so careful with the football and partly because he can use his legs to keep a play going longer -- he doesn't have to just throw it away when the pressure's on.  Unfortunately, he doesn't always escape.  And when he avoids a sack, it's with athleticism, not timing.

Feeley, in contrast, is more of a timing guy.  If it's not there, he'll throw it to Lofa Tatupu away.  Garcia is somewhere in the middle, with good speed but also the savvy to get rid of it when nothing's there. 

The contrast is especially stark when you look at how the three players have fared over the past two years, even if you take out this year's Giants game:

Even if you pretend the Giants game didn't happen, McNabb is still getting sacked twice as often as Feeley did during his brief stint as the starter.  Given that that's the exact same pattern we saw last season with three quarterbacks, it seems fair to suggest that it's not just a coincidence.  McNabb is more sack-prone.

It's also worth noting that the leaguewide average is 6.5 percent.  Feeley's mark would be the third-best in the league, behind only Derek Anderson and Drew Brees.  So it's not like McNabb is going down at some absurdly high rate, it's just higher than we probably should be seeing, given the quality of his line. 

None of this is meant to bash McNabb.  As George pointed out, it's better to take a sack than throw a dumb interception (although throwing it away can be the best option).  And McNabb clearly hasn't been 100 percent all season, which has affected his ability to move and avoid the rush.  But when we're evaluating players after this season mercifully draws to a close, we'll need to understand that the line hasn't taken the step backwards that the statistics would first suggest.