The depletion of our defense was more than two guys. Those two guys were huge, but that was not its not the whole story.
As much as you'd like to believe "next guy in" stuff, you college teams with 20 hour weeks and little experience can fill gaps without significant drop off. You only have so much time with starters playing together, so your back up just isn't going to get the same practice time. Our starters were quite good and our back ups were green. Some of that is recruiting, some is bad luck, but mostly that's just college football. You can lose as many defensive starters as we did and win.