On Monday, I highlighted five potential breakout offenses for 2013, using advanced metrics to identify units that were much better last year than conventional stats indicated and have the key components to be even better this season.
The same concepts hold true for evaluating the potential breakout defenses. Because of the different offensive tempos in modern college football, per-game statistics can't accurately assess the quality of a unit. Numbers become skewed by hurry-up teams -- positively toward offenses and negatively toward defenses.
Regardless of pace, the objective of defensive football is still to keep the opposing offense from scoring. How well that goal is achieved just has to be defined by rates instead of raw box-score numbers. When we look at stats this way, surprises usually emerge, such as the following five defenses that were undervalued last season and should begin to earn more respect in 2013.

Oregon Ducks
The Ducks' defense is similar to Alabama's offense; both teams have built their reputations on one side of the ball, which causes the other side of the ball to be taken lightly by casual fans.
Don't be fooled by Oregon's ranking of 44th in yards allowed per game last season. The Ducks had one of the more effective defenses in college football, and that's shown through the Expected Points Added metric, which evaluates how much each phase of the game contributes to winning. The EPA numbers are adjusted for the strength of the opposing unit, which means that defenses are judged, in part, by the quality of the offenses they face.
Last season, Oregon ranked sixth in the nation in adjusted defensive EPA, which takes into account the numerous times that the Ducks' defense either scored a TD or set up the Oregon offense in scoring position with a turnover. The Ducks led the Football Bowl Subdivision in both forced turnovers (40) and interceptions (26), four of which were returned for a touchdown. Because of that, the defense that ranked 56th in passing yards allowed per game was rated second nationally in adjusted pass defense EPA.
So what does this mean for 2013? Normally, a defense that lost as many key players as Oregon did would not be expected to repeat its performance the next season, but this program is better prepared than most. Because an up-tempo offense has a way of wearing down its own defense in addition to the opposition's, the Ducks rotate more defensive players than, perhaps, any team in college football, often going three deep at most positions. This means that Oregon's new starters always have playing experience.
While statistics show that it's incredibly difficult to force a large number of turnovers with regularity, it's worth pointing out that the Ducks ranked second in the nation in 2010, so the success in 2012 seems much less random.
The Oregon program reached new heights under Chip Kelly, and even though he's gone, the momentum should continue. The program's higher profile has attracted a higher level of recruits, which should be evident in the talent upgrade the Ducks have shown on defense. With players who are bigger and faster than Oregon has ever had, the unit should continue to improve in conventional areas, such as yards allowed and red zone stops. If it can do that and still force about 30 turnovers in 2013, the Ducks should finally earn national recognition as the difference-making defense they've been for the past three seasons.