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

For comparison purposes, the mid-year defensive review can be found here. The numbers haven’t changed appreciably, neither has the season story for the defense.

Most pre-season prognosticators believed the Achilles’ heel of the Irish defense would be stopping the run. While the numbers show this to be a weakness, the run defense isn’t as poor as it appeared this year. In fact, as it was six games into the season, the defensive numbers for the Irish are quite respectable.

The following is a statistical review of Notre Dame’s defense for the 2008 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 12-9-2008.

There is a host of statistics that could be analyzed and compared. In the interest of brevity I have parsed the data into a manageable amount, presented in tabular form.

The Opponent Average and Opponent Average Rank columns below refer to the average offensive values for Notre Dame’s opponents. The Notre Dame and Notre Dame Rank columns refer to the Irish defense. Comparing the numbers in this manner benchmarks Notre Dame’s defensive performance to their competition.

Let’s Start With Efficiency

Defensive Efficiency

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The Irish defense performed average or better creating turnovers, stopping opponents on third down, and inside the red zone.

On the year, the Irish created 23 turnovers, a shade under two per game. This isn’t a mind-blowing number, but it is certainly above average.

Additionally, the Irish held opponents to less than a 34 percent conversion percentage on third down (23rd in the country). In other words, the Notre Dame defense was able to get off the field on two out of every three third downs.

This success was largely due to the Irish winning the battle on first and second down. On the year Notre Dame’s opponents faced third and five or more yards better than 81 percent of the time. By playing well on first and second downs the Irish offense was able to maximize their chance for success on third down.

While opponents’ red zone scoring percentage is high (81 percent), only about half of their possessions inside the Irish 20-yard line resulted in touchdowns. Additionally, these numbers were better (significantly better in the case of red zone touchdown efficiency) than the Irish opponents averaged on the year.

In summary, the Irish defense certainly played well enough in the three most important statistical categories (turnover margin, third down efficiency, and red zone efficiency) to be successful. The offense simply didn’t hold up their end of the deal.

It’s A Totalitarian State Of Affairs

Total Defense

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In terms of total offense, the Irish defense certainly graded better than their opponents. Notre Dame surrendered fewer points per game, yards per play, touchdowns, and yards per game than their opponents’ offenses averaged. This was good for an average ranking of 39 in total defense.

The Irish defense allowed 2.5 touchdowns per game (one through the air and 1.5 on the ground) en route to giving up 22.3 points per contest. Notre Dame also allowed five yards per play, with a season high mark of 6.8 against the Trojans.

In both points per game and yards per play, the Irish defense was slightly better than their opponents’ averages. Notre Dame also gave up a respectable 327.5 yards per game, just about what their opponents gained.

All in all, the total defense numbers aren’t indicative of a dominating performance. But given the lack of talent in the front seven, defensive coordinator Corwin Brown and assistant head coach Jon Tenuta certainly did a good job working with what they had.

Facing The Run

Rushing Defense

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On the surface the Irish run defense appeared pretty poor. A closer look indicates that it was more average than inept.

With the exception of Navy, Notre Dame allowed nearly all their opponents to rush for the number of yards they averaged for the year. Again, surrendering nearly 143 yards per game isn’t great, but-when compared to the opponent rushing averages-sizes up quite well.

Stopping the run was certainly the weakest point of Notre Dame’s defense. However, it wasn’t a glaring deficiency for many games this season.

Anything But Airing It Out

Passing Defense

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The strength of the Irish defense is against the pass. While Notre Dame allowed opponents to throw for about as many yards as they averaged (184.8 compared to 181.2), they did so while forcing opponent offenses to operate less efficiently than they are normally accustomed to.

The Irish held opponents to 0.6 yards less per passing attempt (5.9 compared to 6.5) and one yard less per completion (11.1 compared to 12.1) than they average. The former ranks 17th in the country. Also ranked 17th in the country was the Irish completion percentage as opponents only completed 53 percent of their passes against the Irish.

Notre Dame also recorded 13 interceptions while only giving up 12 touchdowns through the air. While 13 picks is nothing to write home about, only 19 other teams allowed fewer passing touchdowns.

The Irish also improved their ability to get to the quarterback over the last six games. After recording only seven sacks through their first six games, the Irish called off the dogs and began taking fewer risks. The decreased blitzing frequency correlated to an unexpected increase in sack production as the Irish nearly doubled the number of sacks they recorded in the second half of the season.

Relying On The Big One

Notre Dame allowed 28 big runs (2.3 per game) and 27 big passes (2.3 per game) on the year as opponents ran just over 65 plays per game. In other words, roughly seven percent of opponents’ snaps resulted in a big play.

These big plays accounted for roughly 125 yards (38 percent) of offense per contest. In other words, less than ten percent of opponents’ plays resulted in nearly 40 percent of their offense. Without these big plays the per play average for Irish opponents dips from five per play to 3.3, exactly the per play average of the Irish offense without big plays.

Also excluding big plays, Irish opponents averaged only 2.8 yards per rush, 3.9 yards per pass attempt, and eight yards per completion. Like the rest of the defensive statistics, these values are respectable but not overwhelming.

In Summary…

Despite a lack of quality and quantity among the ranks of the front seven, the Irish defense played well enough for Notre Dame to beat nearly every opponent they faced this year. They weren’t dominating, but they certainly were effective and efficient.

While they struggled to stop the run, they did manage to force turnovers, play well on third down, force field goal attempts in the red zone, and minimize big plays. As the talented younger players in the front seven matures, this unit figures to become a strength of the team.