Virginia Tech's defense has consistently been among the best in the ACC since the Hokies joined the league in 2004. It's one of the primary reasons the Hokies have claimed three conference titles and played for another in five seasons.
However, the Hokie D wasn't nearly as dominant in 2008 as we've been used to. While the numbers on the surface show that the Hokies were tops in the league in yards allowed per game in league play, looking deeper reveals that there was plenty of room for improvement.
In my opinion, one of the main reasons the Hokies led the ACC in yards allowed per league game is how few plays they faced. Despite playing one more conference game than 10 of the league's teams, Tech's D saw 514 plays (57.1 ppg), third fewest in the conference. By contrast, FSU faced the fewest plays during league play with 490, but saw more per game (61.3). Boston College, who like the Hokies played in the ACCCG, faced a league-high 570 plays in its nine games.
| Year | YPG | Rank | YPP | Rank |
| 2004 | 261.8 | 2nd | 4.4 | 3rd |
| 2005 | 239.2 | 1st | 3.9 | 1st |
| 2006 | 221.0 | 1st | 3.9 | 1st |
| 2007 | 286.4 | 2nd | 4.2 | 2nd |
| 2008 | 267.8 | 1st | 4.7 | 5th |
When you look at yards per game allowed, the Hokies were fifth in the ACC during league play behind Clemson, BC, UVa and Wake Forest. While 4.7 ypp is a good number, it doesn't stack up when compared to previous Tech defenses.
| Year | YPC | YPA | YPP | RZ% | 3D% |
| 2004 | 3.4 | 5.9 | 4.4 | 87.5 | 30.9 |
| 2005 | 2.6 | 5.1 | 5.2 | 65.4 | 29.9 |
| 2006 | 2.9 | 5.0 | 3.9 | 73.3 | 26.1 |
| 2007 | 2.4 | 5.5 | 4.2 | 69.2 | 26.6 |
| 2008 | 3.2 | 7.0 | 4.7 | 90.0 | 31.0 |
| Total | 2.9 | 5.7 | 4.5 | 75.7 | 28.8 |
I think Tech's yards per carry went up in 2008 because of how good the league's run games were this season. Also, Tech lost three key players in stopping the run game in Xavier Adibi, Vince Hall and Brandon Flowers.
But the ypa jump is startling. Virginia Tech dropped to No. 9 in the ACC in 2008 after being in the top three in the ACC in ypa against its first four years. And the drop came despite the Hokies having the best pass rush in the ACC. They were able to put pressure on the QB, but still allowed tons of yards through the air.
Cornerbacks Stephan Virgil and Macho Harris had solid seasons. However, miscommunication and struggles in the middle of the secondary with Kam Chancellor and Dorian Porch/Davon Morgan led to a lot of big plays.
A lot of things have to go right for Tech's ypa number to improve in 2009. The Hokies lost Macho Harris, meaning Virgil will move to boundary corner and be left in man-to-man coverage more often than he was in 2008. The winner of the field corner derby, which right now is Rock Carmichael, will have to step up and do as good a job at the position as Virgil did last year. And, the play in the middle of the secondary has to improve.
We've seen signs of improvement from Chancellor and Porch/Morgan in the Orange Bowl (which Morgan missed) and in spring practice. However, we won't know for sure until the Hokies face Julio Jones in the Georgia Dome whether the pass defense will be better or worse this season.
Tech also gave up its highest red zone scoring percentage to ACC foes and highest third-down conversion rate in 2008. Tech's inability to halt drives on third down and keep opponents from scoring deep in their own territory probably contributed to their first three-loss ACC season.
Despite having a weaker defense than they are used to having, the Hokies were able to overcome it and win the ACC. I think some of the credit has to go to the offense for chewing up clock and keeping the defense off the field.
The rest of the credit goes to Bud Foster for how much the defense improved over the course of 2008. As scouts know, you can only rely on stats so much. But at the end of the season, the Hokie D certainly passed the eye test.