With the offense out of the way, it’s time to move on to the defense.

For Notre Dame’s defense the story of 2007 was really the inept Irish offense. The offense didn’t control the ball, frequently turned it over, and often times failed to change the field position. This made playing four quarters of solid football a very difficult task for the Irish defense.

Despite this the Irish defense played well in 2007. Of particular note was Notre Dame’s third ranked pass defense which allowed only 161.6 yards per game. The 2008 version of coordinator Corwin Brown’s defense is seemingly a step in the wrong direction, but the numbers paint a slightly different picture.

What follows is a statistical review of Notre Dame’s defense through the first six games of the season. All statistics have been taken from the official Notre Dame football website and/or the official NCAA statistics website. All numbers are current as of 10-20-2008.

The format follows that of the offense analysis, with one notable exception. The opponent averages and opponent average ranks below refer to the average offensive values for Notre Dame’s first six opponents of the 2008 season. The Notre Dame and Notre Dame Rank columns refer to Notre Dame’s defense.

Give Me Efficiency Baby!

Defensive Efficiency

[table id=68 /]

The Irish defense has been relatively efficient on third down, holding opponents to a respectable 36.7 percent conversion rate. With the exception of the Tar Heels (over 46 percent efficiency on third down) Notre Dame has played stingy defense and gotten off the field on third down.

This third down defense is, in no small part, the result of forcing opponents into long third down distance situations. On the year Notre Dame has forced opponents into third and long 65.8 percent of the time. Additionally, Irish opponents have faced third and five or more yards 81 percent of the time.

The primary problem for Notre Dame has been getting opponents into third down situations. Of the 187 times Irish opponents have had a first down, only 79 have resulted in a third down attempt. In other words, 68 percent of the time opponents only need two downs to move the chains.

Compared to the rest of the country the Irish are also good in the red zone. The 76 percent red zone efficiency for the Notre Dame defense seems large but only 52 percent of opponent possessions inside the twenty result in touchdowns (ranked 36th).

Don’t Get Totally Defensive

Total Defense

[table id=69 /]

The defense is also holding opponents to a fairly low scoring total as evident both in points per game and touchdowns allowed. Despite ranking 74th in yards per game, the Irish are only surrendering a shade over 20 points with a season high 29 coming against North Carolina.

This is certainly indicative of the defense’s bend-but-don’t-break style and 52 percent red zone touchdown efficiency noted above.

It is disconcerting that the Irish allow more yards per play and yards per game than opponents typically post, but both values are inflated by a single game against Purdue when Notre Dame surrendered 462 yards at 6.4 yards per play.

Can I Take A Pass?

Passing Defense

[table id=70 /]

The Irish pass defense has taken a small step back from 2007. Against opponents that throw for about 200 yards per game the Irish are giving up over 231 and rank 91st in the country.

In contrast, Notre Dame is holding opponents to more than a yard per completion and half a yard per attempt less than they average. While 6.1 yards per attempt and 11.1 yards per completion aren’t mind-blowing numbers, they are good for 37th and 47th ranked in the country.

The Irish defense has also held opposing quarterbacks to a pedestrian 54.8 completion percentage. The game-to-game story, however, has been quite different. Notre Dame allowed San Diego State and Michigan State to complete less than half their passes but allowed Michigan and Stanford-two run-first teams-to complete better than 64 percent of their pass attempts.

Perhaps the most disappointing defensive statistic is the number of sacks recorded by the Irish defense. Despite the addition of notoriously aggressive assistant defensive head coach Jon Tenuta, the Irish rank near the bottom of the country in sacks.

As discussed here, the inefficiency in pressuring opposing quarterbacks can be attributed to loose coverage on the outside coupled with an aggressive front seven. The play of the secondary and front seven are in contrast to each other and prevent the defense from stopping short passing offenses, the perfect answer to Tenuta’s blitz-happy scheme.

I Guess We Knew It Would Be a Weakness

Rushing Defense

[table id=71 /]

If there is one glaring weakness it is stopping the run. While fairly stout on the ground in the red zone, Notre Dame ranks 63rd in the country allowing 136.3 yards per game. This is only respectable because it is on par with the average rushing attacks of Irish opponents.

The yards per carry story is different. Against opponents averaging only 3.7 yards per rush Notre Dame has allowed 4.4 yards per carry including giving up 6.1 yards per carry to a mediocre Boilermaker rushing offense.

The offensive game plan seems to be designed to mitigate this weakness. If Notre Dame can score early and often it will force opposing defenses to abandon the run.

What Does It All Mean?

In some ways the story of Irish defense is directly opposite to that of the offense. While it appears that the Irish offense is dramatically improved, the numbers tell a different story. On defense, however, a seemingly porous unit has posted respectable numbers.

Four defensive statistics combine to tell the story.

The Irish surrender 231 yards per game through the air, have only sacked the quarterback seven times, allow opponents to gain 4.4 yards per rushing attempt, and only force a third down on 42 percent of first down series. This translates into a bend-but-don’t-break defense that gives up yards but stiffens and guards against touchdowns in the red zone.

This type of defense is a direct contradiction of Tenuta’s mentality. While part of the story is certainly poor execution, a commitment to one philosophy would go a long way to improving an already adequate defense.