I am impressed with our overall defense as well, especially considering the amount of youth we are forced to play. Having said that, we are only 10th overall in run defense in the SEC.
In the interest of full disclosure though, I wonder where our rush defense ranks if you throw out the 4th quarter vs OU, UGA, & UF? We have faired pretty well considering our depth on the defensive line through three quarters, but we get worn down, perhaps as a result of our own offense's ability to sustain drives over the span of an entire game. Samaje Perine, Todd Gurley, and Matt Jones all managed half of their total rushing yards in the 4th quarter against a worn down defense.
If the offense could help to keep them off the field by keeping drives alive in the 4th quarter, it would go a long way towards preserving those defensive efforts instead of seeing them ruined late in games.