As college football offenses continue to evolve in an effort to become more versatile and explosive, defenses have had to keep pace.

Alabama traded in its physically-imposing linebacker mold to bring in players who can play on any down and cover receivers in the slot. That’s just one example of a trend that has become common in the SEC.

RELATED: Predicting which SEC offenses will score more, less in 2017

There are a few dominant defenses in the conference, some that are looking to take the next step and the remainder that have several holes to fill.

Let’s take a look at which defenses will improve this fall and those that will slide back.

Alabama

Last year’s PPG allowed: 13.0

Projected 2017 PPG allowed: More

If Alabama somehow improved upon last year’s numbers, its 2017 defense would go down as possibly the best in college football history. That’s only because the Tide’s 2016 unit is already in that conversation. It’s tempting to say that Alabama is going to take a step back next season, and it’s very likely it will, but Nick Saban reloads year after year.

This season will probably be remembered as the growing year for Alabama’s next core of elite defenders, which means there should be expected regression.

How much? Don’t expect a lot. Alabama has allowed more than 15 points per game in a season exactly once since 2008.

Arkansas

Last year’s PPG allowed: 31.1

Projected 2017 PPG allowed: Slightly fewer

Arkansas finished 10th in the SEC in scoring defense in the SEC last season, but Bret Bielema has taken steps to fix it. He promoted defensive backs coach Paul Rhoads to defensive coordinator, and he will help them implement a new 3-4 scheme to give the defense greater flexibility. Arkansas will need to replace a few veterans, most notably inside linebacker Brooks Ellis, but there are six starters returning in 2017.

Auburn

Last year’s PPG allowed: 17.1

Projected 2017 PPG allowed: Slightly fewer

With the loss of Carl Lawson and Montravius Adams, Auburn’s defense could take a small step back. But the Tigers have enough talent to overcome those losses, which is what we’re betting will happen. Marlon Davidson impressed as a freshman, and the defensive line has a strong blend of depth, talent and upside. Tre’ Williams and Deshaun Davis are two effective linebackers, and the secondary returns a strong core of veterans.

Florida

Last year’s PPG allowed: 16.8

Projected 2017 PPG allowed: More

Florida has lost a lot of defensive talent over the past two years, and it’s time to see whether Jim McElwain’s recruits will equal those brought in by Will Muschamp. There are plenty of defenders to be excited about, including David Reese, Cece Jefferson, Jabari Zuniga and Chauncey Gardner, but it will be tough to replace all of the veteran players on their way out. It’s possible that Florida once again fields a stout defense; it’s just that there’s a good chance the defense also takes a step back.

Georgia

Last year’s PPG allowed: 24.0

Projected 2017 PPG allowed: Fewer

Assuming the star defensive tackle Trent Thompson makes his way back to the team, Georgia could field one of the best defenses in the SEC. Even without Thompson, Kirby Smart has a plethora of talented, versatile defenders to work with. Lorenzo Carter, Roquan Smith and Natrez Patrick are part of a tremendous linebacker corps, and the secondary will get much-needed depth with the arrival of several highly-touted freshmen.

Kentucky

Last year’s PPG allowed: 31.3

Projected 2017 PPG allowed: Fewer

The individual talent is in place for Kentucky to have an above average defense, but it’s up to new defensive coordinator Matt House to make that happen. Taking over for D.J. Eliot, House has some nice players at his disposal. Jordan Jones, Denzil Ware and Josh Allen are a strong trio of linebackers and secondary is loaded with experience. If the Wildcats can figure out a way to utilize the players on hand, they could surprise a few teams.

LSU

Last year’s PPG allowed: 15.8

Projected 2017 PPG allowed: Slightly more

LSU’s first season with Dave Aranda as the defensive coordinator was a success. The Tigers allowed the fewest points per game since their 2011 SEC championship season and limited Alabama’s potent offense to just 10 points. Aranda undoubtedly has a plan in place to improve on last season, but he’s losing a lot of veteran NFL talent, including All-SEC performers Kendell Beckwith and Tre’Davious White, and Jamal Adams, who left early but is a projected first-round pick.

LSU is one of the few schools capable of reloading without taking a big step back, but it’s possible that the Tigers struggle a little bit more than last year.

The Tigers allowed 22.0 or more points per game three times in the past nine seasons.

Mississippi State

Last year’s PPG allowed: 31.8

Projected 2017 PPG allowed: Fewer

Mississippi State finished 13th in scoring defense in 2016, but the Bulldogs have taken an unusual approach to fixing that problem. New defensive coordinator Todd Grantham will have seven new JUCO prospects to work with on defense. With only four returning starters and this massive haul of experienced newcomers, the defense will look entirely different in 2017. Grantham had success at Georgia and Louisville, so we’d bet on him coaching up players like Jeffery Simmons, Chauncey Rivers and Johnathan Abram.

Missouri

Last year’s PPG allowed: 31.5

Projected 2017 PPG allowed: Fewer

It’s hard to imagine Missouri regressing farther. The Tigers allowed almost twice as many points per game in 2016 as 2015 (16.2). A confusing scheme and several injuries plagued them all season, but things improved slightly once Barry Odom took over the defensive play calling, something he will continue to do this fall.

While the injuries hurt Missouri last year, they allowed young players like Cale Garrett and Ronnell Perkins to earn valuable playing time. The Tigers will need to replace Charles Harris and find some depth on defensive line, but they shouldn’t have another disastrous season on defense.

Ole Miss

Last year’s PPG allowed: 34.0

Projected 2017 PPG allowed: Slightly fewer

The Rebels’ exciting “Land Shark” defense seems like a distant memory. A porous run defense plagued Ole Miss all season, and the secondary didn’t fare much better. Fortunately, there are some young linebackers like Donta Evans and incoming freshman Breon Dixon to build around. If Ken Webster returns from injury, it would have a positive impact on a young secondary, but that’s far from a guarantee. New defensive coordinator Wesley McGriff will bring along some scheme changes should make things easier for the players.

South Carolina

Last year’s PPG allowed: 26.5

Projected 2017 PPG allowed: Slightly fewer

Will Muschamp got the most out of his defense last season, but it will still take another season for him to have a depth chart full of his players. The Gamecocks return a talented secondary that should benefit from the addition of Jamyest Williams, a dynamic freshman who could play early. Muschamp will need to replace Darius English and Jonathan Walton, but the return of star linebacker Skai Moore is an added boost. South Carolina will likely have incremental improvement, which is something fans should be pleased with.

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Tennessee

Last year’s PPG allowed: 28.8

Projected 2017 PPG allowed: Slightly more

After shutting out Tennessee Tech, the Vols allowed 35.5 points per game over the final four games of the season, including 45 points in their loss to Vanderbilt. To be fair, injuries took their toll, but there were apparent problems from the beginning. Now, Tennessee must replace key veterans like Derek Barnett, Jalen Reeves-Maybin and Corey Vereen. There is some nice talent on hand for Bob Shoop to work with, and the addition of Brady Hoke as defensive line coach is certainly interesting, but there’s not a lot of confidence in the Vols defense right now.

Texas A&M

Last year’s PPG allowed: 24.5

Projected 2017 PPG allowed: Slightly more

It’s likely that A&M’s defense performs close to last year’s unit, despite the loss of Myles Garrett and Daeshon Hall. The Aggies have some underrated players on the defensive line that could perform better than expected. Shaan Washington’s departure will be felt at linebacker, but Richard Moore and Otaro Alaka will return to compete with a strong incoming linebacker class. Armani Watts is one of the best safeties in the SEC, but the Aggies’ corners need to have a better year in 2017.

Vanderbilt

Last year’s PPG allowed: 24.0

Projected 2017 PPG allowed: More

The loss of All-American linebacker Zach Cunningham is a major blow. Cunningham was the runaway leader in tackles and tackles for a loss, but the majority of the front seven will return. Oren Burks, who had 59 tackles, 6.5 tackles for a loss and 3.5 sacks, is now Vanderbilt’s best linebacker, and incoming freshman Dayo Odeyingbo could join his brother, Dare, on the defensive line sooner rather than later. The Commodores are also losing Torren McGaster, their best cornerback from a secondary that finished last in the SEC with just five interceptions. Only three teams in the nation had fewer.