Not every 3-4 defense is alike. From a 3-4 look, you can either choose to attack the backfield with voracity or play as passively as possible. Alabama falls somewhere in the middle, and Notre Dame skews significantly toward the latter. The Tide rarely rush more than four defenders at the passer (until third-and-long, anyway, when they send five or six and get to your quarterback within about 0.4 seconds), but you never really know where those four pass rushers are going to come from. The Tide are not infinitely aggressive, but they are wild and crazy compared to Notre Dame, which features probably the best 3-4 line in the country (it is difficult to improve on ends Stephon Tuitt and Kapron Lewis-Moore and tackle Louis Nix III), one that is both active enough to generate fierce pressure on its own (those three players have combined for 29 tackles for loss and 21.5 sacks) and big enough to occupy and entire offensive line by itself (the three average 6'4, 312 pounds).
Notre Dame, of course, also features an inside linebacker so good that he almost won the Heisman. Manti Te'o's stats may be some of the oddest you'll see from a star linebacker, but they reflect the odd, complete game Te'o brings to the table. Te'o plays the role, basically, of two different linebackers on any given play: a run-stopper and a third safety; meanwhile, the three-man line plays the role of four linemen. Good luck, then, against that 13-man defense. As with the Notre Dame offense, the Irish defense doesn't take any more risks than it has to, and why should it? The Irish can generate a numbers advantage on virtually every play of the game without doing anything crazy.
Only three opponents have averaged even 5.0 yards per play against Notre Dame this year: Navy (5.7, mostly after the Irish had built a solid lead), Miami (5.4, again mostly after the Irish had built a solid lead) and USC (5.5). Meanwhile, Alabama has been held under 6.3 yards per play just once all year (4.7 against Ole Miss, strangely enough). Alabama does what it does, and it works. But can the Tide carve out the same advantages against a 13-man Irish defense?
