Is the Seattle Seahawks' Secondary Overrated?
It's easy to forget that the Seattle Seahawks started their season off 3-3, and the team, especially the secondary, didn't look a thing like it did in 2013.
After Week 7 concluded -- a loss to Austin Davis' St. Louis Rams -- the Seahawks' defense, per our Net Expected Points (NEP) metrics, ranked 17th in the NFL. The rush defense came in as the fourth-best unit in the league, while the secondary -- the piece of the defense that carried them to a Super Bowl victory last year -- was fourth worst among all 32 NFL teams.
It wasn't what we expected from the Seahawks.
But from Week 7 on, everything changed. Seattle gradually improved on defense, and by the end of the year, their schedule-adjusted pass defense ranking was third. Everything was right in the world. Or, at least Richard Sherman's world.
When you look at Seattle's opponents down the stretch though, you start to wonder if all of this improvement was schedule related. Sure, the rankings I listed above are adjusted for strength of opponent, but the Seahawks, hypothetically, could have just really dominated bad opponents, helping their cause.
And then there was this tweet sent by our good friend Trey Wingo earlier today:
1st six weeks of season Seattle played toughest QB's based on QBR, went 3-2. Since week 7? Only Texans and Browns played weaker group QBs
— trey wingo (@wingoz) January 13, 2015To Trey's point, the Seahawks faced Aaron Rodgers, Philip Rivers, Peyton Manning and Tony Romo in four of their first five games this year. After that fifth contest, the best quarterback that Seattle faced -- analytically, at least -- was Eli Manning.
Maybe there's something to this. Maybe the Seahawks' numbers look so good because they slaughtered bad quarterbacks, all while losing just one game since October 19th.
Is the Seahawks' secondary actually overrated?
To find out, I charted each quarterback performance against Seattle this year, noting the Passing NEP compiled by these signal-callers. Dividing the Passing NEP total by the number of drop backs the quarterback saw during his game against Seattle gave me the number of expected points added by the Seahawks' opposing quarterback on a per drop back basis. I simply compared this average to his season-long one -- was there a difference? Were the most significant differences only from really, really bad quarterbacks?
Take a look.
| Week | Quarterback | Passing NEP | Per Drop Back | Season Average | Difference |
|---|---|---|---|---|---|
| 1 | Aaron Rodgers | -4.75 | -0.13 | 0.34 | -0.47 |
| 2 | Philip Rivers | 19.84 | 0.52 | 0.18 | 0.34 |
| 3 | Peyton Manning | 5.43 | 0.11 | 0.27 | -0.16 |
| 5 | Kirk Cousins | 7.54 | 0.20 | 0.09 | 0.11 |
| 6 | Tony Romo | 13.72 | 0.42 | 0.31 | 0.11 |
| 7 | Austin Davis | 11.57 | 0.53 | -0.04 | 0.57 |
| 8 | Cam Newton | -5.89 | -0.24 | 0.04 | -0.28 |
| 9 | Derek Carr | -11.41 | -0.27 | -0.07 | -0.20 |
| 10 | Eli Manning | -0.5 | -0.01 | 0.10 | -0.11 |
| 11 | Alex Smith | 1.79 | 0.11 | 0.10 | 0.01 |
| 12 | Drew Stanton | -8.13 | -0.28 | 0.03 | -0.31 |
| 13 | Colin Kaepernick | -13.79 | -0.42 | 0.04 | -0.46 |
| 14 | Mark Sanchez | -7.69 | -0.33 | 0.15 | -0.48 |
| 15 | Colin Kaepernick | -4.06 | -0.16 | 0.04 | -0.20 |
| 16 | Ryan Lindley | -13.54 | -0.28 | -0.12 | -0.16 |
| 17 | Shaun Hill | -14.37 | -0.35 | 0.01 | -0.36 |
Before I get into what the chart shows, keep in mind that, among quarterbacks with at least 200 drop backs this season (37 of them), the average Passing NEP per drop back rate was roughly 0.10. The reason this number isn't zero is because, quite simply, we're watching a pass-friendly league and it's more efficient than running the football.
Seattle faced six quarterbacks this season who were at least average on a per drop back basis. Among these quarterbacks, Philip Rivers and Tony Romo were the only two who played "good" games -- games where they surpassed their season-long Passing NEP per drop back average.
Seattle's "best" games -- matchups where they held the opposing quarterback to a Passing NEP per drop back rate that was far below their season average -- came against Mark Sanchez, Colin Kaepernick and, would you look at that, Aaron Rodgers.
While they definitely feasted on poor competition, it doesn't appear we can blame a rise in play from the Seahawks' defense on just that. Instead, it seems like the secondary had a couple of hiccups, specifically against the Chargers and Cowboys, and have just been close to unbeatable since.
So no, the secondary isn't overrated. It's really, really good.
