No. 1, yet room to improve

TUSCALOOSA, Ala. -- Somehow, someway Alabama's defense in 2012 finished in the top 10 of nearly every major statistical category: pass defense, rush defense, red-zone defense, scoring defense. On and on the list went, including a spot atop the most coveted ranking of total defense. The Crimson Tide gave up just 250 yards per game and a total of 153 points all season.

It was an imperfect arrangement held together by Nick Saban and defensive coordinator Kirby Smart, a defense with individual flaws concealed well within the structure of the whole. It wasn't as dominant as the 2011-12 group that was downright historic, nor was it as smothering as the unit that put Colt McCoy on his backside in 2009. But it was good enough. And with only a handful of starters leaving, it stands to improve.

But first, spring practice. Smart and Saban have holes to fill on nearly every layer of the defense, starting up front on the defensive line and on back to the cornerback and safety level, where two starters are off to the NFL.

1. Secondary concerns

It might all start up front on defense, but the most obvious concern for Alabama is its secondary. It was the Tide's Achilles' heel last season against above-average passing teams (see LSU, Texas A&M, Georgia), and that was with a shutdown cornerback in Dee Milliner. Well, he's gone now and so is the leader of the unit, safety Robert Lester.

Of the potential replacements, there are few with notable experience. Safety Landon Collins is an upgrade in terms of athleticism, but with little evidence on hand it's hard to translate what he has done on special teams into a starter's reps. The same goes for cornerback Geno Smith, a likely replacement for Milliner now that Jon Fulton is dealing with a turf toe injury. The former four-star prospect played well as a freshman last season, but he arrived on the scene late and wound up a third cornerback on the field.

The whole issue of the secondary is further complicated by the coaching turnover. Saban has expressed confidence in new secondary coach Greg Brown, but it's hard to imagine it won't take time to learn the personnel and reacclimate to Saban's scheme.

2. Improving the pass rush

It wouldn't be unfair to place some of the blame for a lackluster secondary on the front seven, specifically the pass-rushers at defensive end and outside linebacker. In fact, Saban said as much during the season, when he pointed out that the problem was two-fold. He said, "A combination of not rushing on a consistent basis and not covering on a consistent basis, that has been one of the problems that we've had."

The reason? A lack of playmakers at both levels, though the most noticeable missing link was at edge-rusher. Courtney Upshaw and Dont'a Hightower have been gone for more than a year now and a worthy successor hasn't been found. Adrian Hubbard might end up being the man to pressure the backfield from outside linebacker, but he won't be able to do it alone. Either Xzavier Dickson, Jeoffrey Pagan or some other up-and-comer must get involved to turn up the heat on the quarterback and relieve the secondary.

3. Retooling the defensive line

The trenches in Bryant-Denny Stadium on Saturdays won't look the same. The offensive line must replace three starters, as will the defensive line. Three major contributors -- nose guard Jesse Williams and defensive ends Damion Square and Quinton Dial -- are all off to careers in the NFL, leaving a void in experience and leadership.

Replacing their production wasn't made any easier when Freshman All-SEC selection D.J. Pettway was booted off the team for his involvement in a burglary in February. There are, however, some talented players waiting in the wings, not to mention the return of rising senior Ed Stinson, who started all 14 games this past season. Jeoffrey Pagan is poised to garner more reps as a junior and talented rising sophomore LaMichael Fanning has showed flashes of brilliance.

The most intriguing prospect might be freshman Dalvin Tomlinson, who redshirted last season. Saban mentioned on a few occasions that, if not for an injury sustained in high school, Tomlinson might have been a third-down option at defensive end in 2012.

4. Finding more playmakers

Defense, especially the scheme created by Saban, is predicated on 11 players doing their jobs and playing within the system. If an end becomes too eager to sack the quarterback and rushes too far upfield, it can throw off the entire play. It's gap-assignment football that makes the Tide's defense special, and it's why the stats don't usually show a ton of sacks or interceptions.

But that doesn't mean the system doesn't allow for playmakers. In fact, players such as Mark Barron, Marcel Dareus and Courtney Upshaw are what make it special. They draw focus away from the offensive coordinator and free up others to make plays. Without Upshaw, Dont'a Hightower doesn't have 11 tackles for loss in 2011. Without Barron, Robert Lester doesn't have eight interceptions in 2010.

In 2012, Alabama lacked those type of playmakers on defense. C.J. Mosley was one of the best linebackers in the country, but he couldn't do it alone. He needs others around him to help lead the charge.