Dedfischer posted a very interesting analysis of TCU's defense, the product of Gary Patterson's fertile defensive imagination. A few comments and amplifications:
Dedfischer is correct to focus on the performance of the defensive line. Perhaps the performance of no other unit on the team better forecasts TCU’s fortunes than its defensive line. The evidence lies in 2004, when the Horned Frogs had to rebuild the entire unit. The young players struggled, and with them, the whole team suffered. Because opposing quarterbacks had more time to find open receivers, the Frogs were susceptible to the pass, from the first game– a narrow overtime win over Northwestern– to the last– a sixth loss, taking the Frogs out of bowl season altogether. Texas Tech’s gaudy show against TCU, the famous 70-35 loss in Lubbock, was the low point of a low season. While there were other factors at play, poor pressure up front was the fulcrum on which the season’s fortunes tilted.
The team’s fortunes changed dramatically with the host of returners on the line in 2005, and the emergence of Chase Ortiz and Tommy Blake at the ends. Again, line play was not the only improvement, but increased pressure up front paved the way for better defense generally. Better defense took pressure off Jeff Ballard at quarterback, who, by the end of the BYU game, held the reins and set the Frogs’ present course.
Gary Patterson has been running his 4-2-5 since his days as defensive coordinator at New Mexico. At TCU, his schemes did not show very much fundamental change until 2009, when the number of safety and corner blitzes dramatically decreased. This trend has continued in 2010. I only can speculate as to the reason for this change, but speculate I will. I believe the quality of TCU’s defensive tackles has increased in recent years. Defensive (and nose) tackle are the hardest positions to recruit in college, and TCU has found and developed some excellent interior linemen lately. The push these players create, and the obstacle they become to opponents’ run games, allows the Horned Frogs to delegate almost all of the quarterback pressure to the big men up front. That leaves seven defenders to play the rest of the field, and with notable result. TCU has held passing attacks to record lows in the last few years. The Frogs have allowed (for them!) higher-than-usual rush numbers, but incredibly low pass totals.