SEC teams annually rank among the best defenses in the nation.

The term “best” defense can be a subjective one, however. There isn’t the perfect barometer when it comes to determining the very best defenses. We looked at some outside sources, such as ESPN’s Football Power Index (FPI) and Bill Connelly’s Havoc Rate, which determines which defenses apply the most pressure through criteria such as pass rushes, tackles for loss and broken-up passes, to name a few.

We took an average score from where teams ranked on both lists to get a look at who the top defenses will be in 2015. Some surprises abound with Clemson and Virginia Tech ranked high on the list and Arkansas making an appearance.

The SEC tallies five teams on our board. Here’s a look at where the SEC stands among some of the nation’s top defenses:

1. Alabama

Alabama has owned the SEC’s top rushing defense in each of the last four seasons. Make that five in 2015 as the Crimson Tide rises once again among the nation’s elite with a front-seven that could challenge among the program’s best ever.

A’Shawn Robinson, Jonathan Allen, Jarran Reed and Reggie Ragland should lead Alabama’s vaunted rushing defense — on a unit that returns seven starters. The Crimson Tide bulked up its secondary during the offseason and should improve upon a pass defense that finished toward the middle of the conference pack in 2015.

Alabama will field a defense this season that boasts 12 defensive players who were five-star recruits coming out of high school.

Base Defense: 3-4
ESPN FPI Rank: No. 2
Connelly’s Havoc Rate: No. 18

2. Ohio State

You don’t win a national title with a soft defense. The Ohio State defense will be among the nation’s best in 2015, thanks in large part to a unit anchored by Joey Bosa. If the unanimous All-American improves upon his 2014, then the Big Ten and beyond is in big trouble. The rising junior tallied 21 tackles for loss, 13.5 sacks and 116 tackles last season for the champion Buckeyes.

The unit finished 19th in the country in total defense, behind six SEC schools. To improve upon that ranking this offseason, Urban Meyer bolstered his defense — which struggled against spread offenses at time last year — by strengthening his depth at linebackers.

Base Defense: 4-3
ESPN FPI Rank: No. 9
Connelly’s Havoc Rate: No. 11

3. Ole Miss

Ole Miss returns with the country’s No. 1 scoring defense and has set its eyes on being among the nation’s best again. The biggest improvement for Hugh Freeze’s defense involved its rush prevention, which dropped its touchdowns allowed from 27 to 9 between 2013 and 2014. Touted DT Robert Nkemdiche played a major role in that improvement, even if his numbers don’t project like that of a player who was the No. 1 recruit coming out of high school.

The Rebels will be without Senquez Golson, who led the SEC in picks (10) last season, and fellow All-American safety Cody Prewitt. But Ole Miss has a more-than-capable secondary, including Tony Conner and JUCO transfers Tee Shepard and Tony Bridges. If Freeze can get improved depth at linebacker, then Ole Miss will be among the nation’s elite defenses again.

Base Defense: 3-4
ESPN FPI Rank: No. 1
Connelly’s Havoc Rate: No. 17

4. Virginia Tech

The Virginia Tech defense is stacked from top to bottom. The Hokies had one of the nation’s best pass defenses in 2014 and should remain among the country’s best. Strengthening the Hokies defense is the return of DT Luther Maddy, who missed all but four games last year to a torn meniscus. He’s tasked with anchoring the Hokies’ front line which returns no starters. Prior to the injury, the senior Maddy tallied 22.5 TFL, 11.5 sacks and 119 career tackles.

Also back is CB Brandon Facyson who missed most of last season with a broken leg. Both only help to strengthen a Virginia Tech defense that is simply going to torment offenses this season. First up: Ohio State.

Base Defense: 4-4
ESPN FPI Rank: No. 3
Connelly’s Havoc Rate: No. 6

5. Clemson

Despite major personnel loses — including DE Vic Beasley, LB Stephone Anthony, DT Grady Jarrett and CB Garry Peters — the Clemson defense promises to be among the nation’s elite again in 2015, having reloaded. Under Dabo Swinney, the Tigers’ defense has become an annual powerhouse, ranking No. 1 on Connelly’s Havoc Rate scale. Thanks in large part to its defense, the Tigers are one of only three teams (Alabama and Oregon) to win 10 games in each of the last four years.

The Tigers finished No. 1 in total defense (260.8 ypg) last year and should return toward the top of that list this season.

Base Defense: 4-3
ESPN FPI Rank: No. 4
Connelly’s Havoc Rate: No. 11

6. TCU

The Horned Frogs will replace six players from last year’s unit, which finished No. 18 in total defense (341.8 ypg). Head coach Gary Patterson has restocked the cupboard, however, with a group that promises to be faster and more athletic. The Horned Frogs will have another loaded offense. How well a young defense can assimilate could be the difference between making the playoffs and sitting on the outside looking in once again.

Base Defense: 4-2-5
ESPN FPI Rank: No. 10
Connelly’s Havoc Rate: No. 2

7. Florida

New Florida head coach Jim McElwain should send deposed Gators coach Will Muschamp a gift basket, or, at the very least, a thank you note. McElwain inherits one of the nation’s best defenses in his first year in Gainesville.

The squad finished second in rush defense and boasts one of the strongest secondaries in the nation led by Vernon Hargreaves III. The defense yielded the least amount of yards (3,957) among SEC teams last season. The Gators will have to cope with the loss of first-team All-SEC DE Dante Fowler Jr. and the potential absence of incumbent tackles leader LB Antonio Morrison to start the season.

If the Gators defense can avoid a slow start like last year, new defensive coordinator Geoff Collins might be proven prophetic with his preseason Twitter hashtag #BDN, aka “best defense in the nation.”

Base Defense: 4-3
ESPN FPI Rank: No. 8
Connelly’s Havoc Rate: No. 5

8. LSU

Les Miles’ group was the No. 1 unit in the SEC last season in total defense (316.8 ypg). Miles brought in Kevin Steele to replace John Chavis (now Texas A&M) as defensive coordinator, yet the unit shouldn’t experience any drop-off in 2015. The temporary loss of Jalen Mills (67 tackles, 3 sacks, 3 interceptions) is a blow to the secondary, as the safety recovers from a broken fibula that will likely sideline him for 4-6 weeks. While the Tigers secondary should be among the nation’s best, Steele will need to reinforce the squad’s pass rush, a weak spot last season for the squad to become truly elite.

Expect Steele to vary the defense often between 4-3, 4-2-5 and 3-4. It’s still somewhat of a mystery how LSU will open the season defensively.

Base Defense: 4-3
ESPN FPI Rank: No. 5
Connelly’s Havoc Rate: No. 24

9. Penn State

Former Vanderbilt coaches James Franklin and Bob Shoop have quickly assembled a potent defense in Happy Valley. The Nittany Lions possess an athletic, versatile and deep roster led by Anthony Zettel. The defensive lineman sacked opposing quarterbacks 8.0 times in 2014 and added an additional 17.0 tackles for loss.

If the Lions front seven can stay healthy and the team shores up its secondary, the Penn State defense could be the best in the Big Ten.

Base Defense: 4-3
ESPN FPI Rank: No. 7
Connelly’s Havoc Rate: No. 15

10. Arkansas

The Arkansas defense was a pleasant surprise in 2014 under first-year Razorbacks defensive coordinator Robb Smith. The group finished No. 10 in the nation in total defense last year, ahead of everyone in the SEC save for LSU.

The unit seemingly flipped a switch toward the end of last season. After allowing an average of 24.7 points per game over the season’s first nine games, the Razorback defense woke up and held opponents to a paltry 7.0 ppg to round out the season — including shutouts on LSU and Ole Miss in consecutive weeks.

The Arkansas defense suffered the departures of Trey Flowers, Martrell Spaight and Darius Philon, but should remain the team’s strength. If Smith can add depth and find some additional playmakers at linebacker, then the Arkansas defense will remain a big asses — and won’t be a surprise any more in the SEC West.

Defense Base: 4-3
ESPN FPI Rank: No. 14
Connelly’s Havoc Rate: No. 7