Seattle's defensive weaknesses
— -- Having once again led the team to a Super Bowl berth, the Seattle Seahawks' defense now looks ready to take its place among the great defenses in NFL history.
This group finished in the top five in the league in a wide variety of categories, including opposing Total QBR, yards per game, yards per play, rushing yards per game, yards per rush, passing yards per game, net yards per pass attempt, first downs per game, time of possession and points allowed per game.
The league-leading points allowed total may be the most important. Since the 1970 merger, Super Bowl teams that had the best scoring defense have a 13-3 record in the Super Bowl and have won seven of the past eight.
These numbers suggest that the Seahawks' defense is impermeable, but this group actually has some significant issues in stopping teams that attack them with a strong rushing attack and high-percentage short passes -- issues that could have them on the losing side in Super Bowl XLIX.
Recurring run defense issues
A good portion of this was evident prior to the NFC Championship Game against Green Bay. During the past two seasons prior to that contest, Seattle had allowed 100 or more rushing yards in 18 games. The Seahawks were 11-7 in those games, which is a far cry from the 18-0 mark they possessed when not allowing 100 or more rushing yards.
Seattle's rush defense woes were even worse when facing a strong ground attack. The Seahawks had faced eight offenses that finished in the top 11 in rushing yards. They gave up an average of 117.4 rushing yards and allowed 100 or more yards in five of those matchups.
This did not bode well for the matchup against the Packers, but Seattle actually did a fairly good job in some measures against Green Bay's ground attack. The Seahawks allowed the Packers to tally a meager 32.1 percent good blocking rate (GBR), which measures how often an offense gives its ball carriers good run blocking (which is very roughly defined as not allowing the defense to disrupt a rush attempt). Anything below 40 percent in GBR is considered an above-average figure, and getting as close as they did to 30 percent is considered a well-above-average performance.
The problem for Seattle is that despite this consistency in stopping the run, the Seahawks still gave up 135 rushing yards. A lot of this was due to their allowing 9.4 good blocking yards per attempt (GBYPA), a metric that gauges productivity on rush plays with good blocking. The median bar in this category is 7.5, and anything above 9 is considered well below average. This shows that when the Packers were able to wall off Seahawks defenders, Green Bay's ball carriers were able to break off quality gains.
Why this is a problem: In the 10 weeks leading up to their win in the AFC Championship Game, the Patriots ranked 30th in yards after contact per carry (1.28). In the last seven weeks of the regular season, the combination of Jonas Gray and LeGarrette Blount helped New England rank seventh in that same metric (1.94).
Extra box defender not a plus for Seattle
Seattle could ostensibly counteract this by adding an additional defender to the tackle box, a tactic known as a loaded defense. This has worked for them quite well in some ways this year, as the Seahawks allowed only 213 rushing yards when loading the defensive front, a total that ranked fourth in the league.
The low yardage total notwithstanding, there are major issues in going this route:
• The Seahawks allowed 1.97 yards after contact per rush on loaded defense plays, which ranked 24th. If this recurs, Blount and Gray could produce some big yardage gains for New England.
• Seattle's pass coverage suffers whenever the team calls for a loaded defensive front, ranking 19th in Total QBR allowed (56.1) in these situations.
• The Pats are almost certain to stay away from rush attempts against a loaded defense. The Patriots ran the ball fewer times than any other team when facing a loaded defense (33).
• New England also fares well when throwing the ball against loaded defenses, ranking 11th in Total QBR in that scenario (66.3) with an 11-1 touchdown-interception ratio.
Why this is a problem: Even if Seattle finds a way to stop the run without a loaded defensive front, it will also have to shut down New England's powerful dink-and-dunk passing game.
The Patriots do a tremendous job on short passes (aerials thrown 10 or fewer yards), ranking second in average time before the pass (2.11 seconds) and third in Total QBR (75.8), touchdowns (24) and third-down conversion rate (48 percent).
By contrast, Seattle's defense ranks 17th in short pass Total QBR allowed (60.2) and 27th in short pass completion percentage allowed (71.6 percent) and had a 13-3 touchdown-interception ratio. The Seahawks haven't done a very good job keeping those types of passes in check, and that was before this secondary suffered injuries to Richard Sherman and Earl Thomas.
Bottom line
The Patriots' incredibly creative play calling assures they will find myriad ways to attack Seattle's defensive soft spots. If those efforts are successful, it could end the reign of the defending Super Bowl champions and potentially ruin the perception that the Seahawks have one of the greatest defenses in NFL history.