Who are the SEC's biggest X factors for 2016?

In new defensive coordinator Dave Aranda's aggressive 3-4 scheme, LSU linebacker Kendell Beckwith could be a Tiger with tremendous upside. Derick E. Hingle/USA TODAY Sports

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Leonard Fournette, Nick Chubb, Chad Kelly, Myles Garrett -- the SEC is stacked with stars for 2016.

But that makes the lesser-known supporting cast so much more important in getting a leg up on the opposition in the ultra-competitive SEC.

Here are the 14 biggest X factors in the SEC for next year:

East Division

Tennessee Volunteers: New defensive coordinator Bob Shoop

Tennessee's defense never ranked higher than No. 7 in the SEC under John Jancek (2013-15), but Shoop has led top-25 units in total defense in each of the past five years, first at Vanderbilt, then at Penn State. He employs a more aggressive system, which should better leverage the Vols' speed, especially with the returns of likely early-round draft picks cornerback Cameron Sutton and linebacker Jalen Reeves-Maybin. With a team that surrendered three double-digit leads last year, Shoop's arrival in Knoxville is just what the scoreboard ordered.

Georgia Bulldogs: DT Trenton Thompson

After registering just two sacks and 11.5 tackles for loss in 2015, Georgia's defensive line desperately needs a playmaker. Thompson, a sophomore, looks ready to make that leap. His development slowed last year (just 2.5 TFLs and half a sack), but the former five-star prospect screams All-American under coach Kirby Smart's watch.

Florida Gators: DT Caleb Brantley

The Gators invaded opposing backfields often in 2015, totaling 101 TFLs, and if that dominance holds steady this fall, Brantley likely will be the catalyst. He showed flashes of pure brilliance in 2015, most notably a five-game stretch in which he registered at least half a tackle for loss in each outing but wasn't always asked to do a ton. That will change in 2016, with Jonathan Bullard and his 17.5 TFLs and 6.5 sacks off to the NFL. Brantley might not be a stat machine (three sacks in 2015), but he is disruptive and athletic.

South Carolina Gamecocks: DE Darius English

Coach Will Muschamp's first order of business on defense will be to amp up South Carolina's pass rush. Opposing quarterbacks were sacked, hit or under duress on only 22.6 percent of dropbacks in 2015, a rate that put the Gamecocks just outside the Power 5's bottom 10. Be on the lookout for English, who could explode at the hybrid Buck spot. His 4½ sacks led South Carolina last year, but allowing the senior to move around more and play standing up or squatting with his hand on the ground should up his value. While he's not the biggest end (6-foot-5, 240 pounds), English has enough straightaway speed to be dominant in his new rusher role.

Missouri Tigers: WR Chris Black

The Alabama transfer might just be the dependable safety net that quarterback Drew Lock needs to get Mizzou humming. Though he never caught fire in Tuscaloosa -- 25 catches for 290 yards in three seasons -- Black is a former 22nd-ranked ESPN 150 prep and is arguably the most talented wideout in Columbia. Consider: Missouri had neither vertical attack (16 catches of 25-plus yards in 2015, tied for 119th in the FBS) nor a single go-to receiver. The Tigers return no one with more than 30 catches or 350 yards last year.

Kentucky Wildcats: New offensive coordinator Eddie Gran

Gran, a Cincinnati transplant, has his work cut out for him 86 miles down I-75 in Lexington. The Wildcats have not ranked higher than ninth in the SEC in total offense and scoring since 2010. Last year was especially egregious, with Kentucky throwing six more picks (16) than touchdowns (10). Unlike his predecessors, Gran is not an air-raid disciple, but his success running up-tempo, pass-heavy attacks at prior stops should excite the fans in Kentucky. Last year his Bearcats' pass offense gained 359.9 yards per game, sixth most in the country.

Vanderbilt Commodores: WR C.J. Duncan

Junior wide receiver Trent Sherfield was a pleasant surprise last season (six games with 50-plus receiving yards), but he'll need a castmate. Enter Duncan, who returns after missing all of 2015 with a leg injury. The versatile junior can line up in the backfield, be used in motion or sit down as a normal receiver. That flexibility is gold, not just for Sherfield but for Vandy's young quarterback. Kyle Shurmur started five games last year as a true freshman, and though he is certainly the most promising signal-caller of the Derek Mason era, his QBR was 17.3. Attention, C.J.: Shurmur needs playmakers to shoulder the load.

West Division

LSU Tigers: The linebackers

Former Wisconsin defensive coordinator Dave Aranda and his attacking 3-4 base arrive in Baton Rouge for 2016. The Tigers will be transitioning from last year's 4-3, and Aranda's scheme, which draws up exotic blitzes from its linebackers, will ask more from the unit in 2016. Speedy defenders like seniors Kendell Beckwith (10 TFLs in 2015) and Duke Riley will help LSU's defensive ends attack the edges.

Alabama Crimson Tide: New defensive coordinator Jeremy Pruitt

Other SEC programs made splashier hires (Bob Shoop to Tennessee, Dave Aranda to LSU), but bringing Pruitt back into the Alabama fold was a no-brainer for head coach Nick Saban. Pruitt cut his teeth in Tuscaloosa before moving on to direct defenses at Florida State (2013) and Georgia (2014-15), where his units ranked top 20 in the nation in scoring and yards per game each year. Alabama has signed 34 ESPN 300 defensive prospects since 2013, so he'll have plenty of talent to help ward off any drop-off from the Kirby Smart era.

Ole Miss Rebels: LB Rommel Mageo

Mageo's decision to take up residence in Oxford as a graduate transfer (Oregon State) is welcome news for the Rebels' defense. The linebacker led the Beavers with 87 tackles last year, so he'll provide a critical, and immediate, boost to a linebacker unit that loses C.J. Johnson and Denzel Nkemdiche (18 starts and 96 tackles combined in '15) and that needs a playmaking complement to junior DeMarquis Gates.

Texas A&M Aggies: The offensive line

In February, head coach Kevin Sumlin brought back Jim Turner for a second stint leading the Aggies' offensive line, and he'll be entrusted with overhauling a thin, inexperienced unit. Texas A&M surrendered 2.9 sacks per game in 2015, tied for 107th in the nation, so Turner's ability to turn around a porous line might just be the key to the Aggies returning to form on offense. In its first year post-Johnny Manziel, A&M maintained a solid 6.3 yards per play (No. 26 in the FBS) but flatlined in 2015 with 5.6 (No. 69).

Mississippi State Bulldogs: Defensive coordinator Peter Sirmon

Sirmon is the latest to cycle through the Mississippi State revolving door of defensive coordinators and is Dan Mullen's sixth coach to hold the spot in eight seasons. The first-time defensive coordinator (he coached linebackers at Tennessee, Washington and USC) will mix in some 3-4 alignments with the Bulldogs' 4-3 base, including a new hybrid end/linebacker spot he calls "viper," which should leverage the team's wealth of defensive ends.

Auburn Tigers: LB Tre' Williams

All three starting linebackers from 2015 are gone (Kris Frost, Cassanova McKinzy, Justin Garrett: 593 combined tackles since 2012), so Williams returns to The Plains as the unit's most experienced Tiger. The departing starters predicted last year that Williams, who came up with 55 tackles and four TFLs in 2015, was ready to take over the D. He'll need to if Auburn has any hope of resurrecting a dormant rush defense. The Tigers allowed 4.5 yards per carry last year, 11th in the SEC.

Arkansas Razorbacks: The running backs

Sophomore Rawleigh Williams III is coming back from a scary neck injury, former QB and now-WR Damon Mitchell is still learning the intricacies of the position, and true freshmen Devwah Whaley and T.J. Hammonds are promising (2016 ESPN 300 preps) but unproven. That leaves senior Kody Walker to take on an expanded role after backing up Alex Collins last year. Walker rushed for at least one TD in four of Arkansas' final seven games -- production that will be critical for a team that ran the ball on 57.8 percent of its plays in 2015 (No. 14 in the Power 5).