5. Alabama Crimson Tide

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The Alabama Crimson Tide has tortured teams like LSU all season long. Their defense suffocates opposing offenses and is holding them to very little yardage and points. The Crimson Tide is tied for first in the nation in total defense (10.6 points allowed per game). They are sixth in the nation in red zone defense, as they allow opponents to score 65 percent of the time when they reach the red zone.

The SEC is a ground-and-pound conference, so the running backs down South do damage against most teams, except for 'Bama. The Crimson Tide is fifth in the nation in rushing defense; they allow 95.3 rushing yards per game.

The Crimson Tide is ranked No. 1 in the nation, and for good reason.

4. Virginia Tech Hokies

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Logan Thomas is a good quarterback, no doubt. He is garnering nationwide attention for his scrambling abilities, but if you closely examine Virginia Tech, you will notice that their defense is making heads turn as well.

The Hokies are third in the nation in total defense (263.1 yards allowed per game). They have had no problem stopping opponents, as they rank fourth in the country in rushing yards allowed per game (95.2) and fourth in nation in passing yards allowed per game (167.9).

More impressively, Virginia Tech ranks fourth in the nation in interceptions, with 17 on the season.

These Hokies are for real.

3. Florida State Seminoles

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Teams in the ACC have been worried about squaring up against the Florida State Seminoles, and for good reason. This talented defense ranks first in the nation in passes intercepted (18). When they traveled to South Carolina to take on the Clemson Tigers, they shut down the Tigers' electric quarterback, Tajh Boyd. After winning 51-14, they proved to the nation that they could contend for the national title at the end of the season.

Florida State has the statistics to back up that notion. They rank fourth in the nation in total defense (274.1 yards allowed per game), and their secondary has shut down opposing quarterbacks all season long. The Seminoles rank first in the country in passing yards allowed per game (147.9).

Keep an eye out for this time when the season comes to an end. They just might be competing for the national title.

2. Louisville Cardinals

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The Louisville Cardinals have absolutely decimated their Big East competition this season. The Cards' defense has been particularly impressive. They rank second in the nation in third down defense, allowing opposing offenses to convert third downs 27 percent of the time. That's pretty low.

The Cardinals also rank sixth in the nation with 73 tackles for loss. Defensive lineman Marcus Smith leads the Louisville attack with 14.5 tackles for loss, good enough for seventh in the nation.

Louisville's opponents have had a problem scoring against their stingy defense this season. Because of that, the Cardinals rank first in the nation in scoring defense; they only allow an average of 10.6 points per game. They also rank second in nation in sacks (3.56 sacks per game).

This Louisville team is scary good, and it's not just because of Teddy Bridgewater.

1. Michigan State Spartans

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It's nearly impossible to sit in first place in the Big 10. It's a tough conference, to say the least. However, with a solid defense, anything is possible. The Michigan State Spartans once again top this list of top defenses in the nation, and it's not by mistake.

This defense ranks first in the nation in yards allowed per game (210.2), first in the nation against the run (43.4 yards per game), and first in nation in yards per running play (1.62).

Good luck trying to run against this Michigan State defense; it will take a miracle to overpower this defense. As a result of their defense holding back opposing offenses, the Spartans are first in the Big 10 Legends Division at 8-1.