It is harder than ever for college football teams to play good defense. That's been apparent the last few years, as up-tempo and spread offenses have become commonplace, and some are among the most successful in the sport. (We're looking at you, Auburn and Baylor.)
Yes, up-tempo and spread offensive attacks have made some pretty good defenses look silly, in part because defenses are now on the field for a lot more plays each game. The FBS average is 71.9 plays per game, up from 67.7 per game five years ago. The NFL average is 65.
We (current and former defensive players) could complain about rule changes that give offenses a huge advantage (i.e., the frenzied pace that doesn't allow defenses to get set, or allowing offensive linemen to block downfield on screens and pass plays), but we don't make excuses. No, what we defenders must do is adapt -- and in turn, we analysts must change the way we evaluate defenses.
It is no longer good enough to look simply at points allowed (this never accounted for scores allowed by the offense or special teams) and yards allowed (this never accounted for yards allowed in a blowout game) to determine good defensive teams.
When I evaluate defenses, the objective factors I rely on most are points allowed per drive (FBS average is 1.97) and yards allowed per play (FBS average is 5.74). These statistics give a better view of how defenses are performing -- regardless of the number of plays they are on the field.
Almost all of my top 10 teams excel in these two areas, and I also factor in my own analysis, after covering games live and breaking down tape, to create this ranking. This subjective part of the ranking tells me which teams are disciplined, and which teams have difference-makers -- things you can't get from the statistics alone.
With those factors in mind, here is my ranking of the top 10 defenses of the 2013 season:
This was the top defense in the country by any measurement. Sparty had the No. 1 defense in yards allowed per play (3.94) and was third in points allowed per drive (0.93) -- and if you prefer the old-school stats, MSU dominated those, too. Additionally, Michigan State's D allowed the fewest rushing yards per game (80.5), fewest yards per rush (2.7) and fewest 10-yard runs (30) in the FBS.