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15 for ’15: Best defensive players in college football
CFB 24/7's "15 for '15" series looking at 15 superlative players in college football for 2015, across dozens of categories, continues with a look at the top defensive players returning this fall.

Size: 6-5, 255
Class: Sophomore
Buzz: The most dynamic young pass rusher in the SEC broke Jadeveon Clowney's league freshman record for sacks with 11.5, more than double anyone else on the team. His quick first step and upfield explosiveness was a nightmare for opponents from the beginning of the season, and new defensive coordinator John Chavis will put Garrett in a great position for another big season. The next step in Garrett's game will be to hold his own better against the power-rushing SEC teams (read: Alabama, LSU, Arkansas) that negated his quickness with brute strength. If Chavis develops that part of his game, Garrett's immediate future is limitless.

Size: 6-1, 230
Class: Junior
Buzz: Whether Jack's side role as a running back continues to trend down or not (38 carries in 2013, 28 in 2014), his place among the Pac-12's top linebackers will only trend up. He's more than just a run stuffer (18 pass breakups in two years), but expect him to register double-digit tackles for loss for the first time in his career this fall. He'll take over more of a leadership role in the Bruins' linebacking corps this fall with the loss of emotional leader Eric Kendricks (Minnesota Vikings second-round pick) at the Mike position.

Size: 6-9, 280
Class: Senior
Buzz: Nobody is quite sure where lines of potential and his production will eventually cross on Oakman's career graph. Somehow, despite Baylor team highs last year in tackles for loss (19.5), sacks (11), quarterback hurries (nine), fumble recoveries (three) and fumbles forced (three), there remains a sense among Big 12 insiders that he's still not fully tapped his vast potential. That might have something to do with the fact that he can overwhelm offensive tackles purely with physical traits and less with technique.

Size: 6-3, 268
Class: Sophomore
Buzz: Barnett piled up 20.5 tackles for loss and 10 sacks for the Volunteers in 2014, but his season was somewhat overshadowed by a dismal year for the team. Still, he was the best defensive freshman in the league. Texas A&M's Myles Garrett was the more hyped freshman of the two, but Barnett was better against the run, and consider this: all 10 of Barnett's sacks came in SEC play, while only three of Garrett's did. Last year, he surprised the league as a first-year starter. This year, he'll sneak up on nobody, and will draw more double-teaming.

Size: 6-4, 236
Class: Senior
Buzz: Nicolas gave some thought to entering the NFL draft early, and as a fourth-year junior with an undergraduate degree already in hand, nobody could have blamed him. Instead, he's back to terrorize ACC quarterbacks one more time. Last year, Nicolas made 72 stops with 18.5 tackles for loss, nine sacks and an incredible 35 quarterback hurries. Expect him to finish more of those this fall. Beyond just rushing the passer, Nicolas has exceptional range as a tackler on the perimeter defending stretch plays. As a freshman in the Russell Athletic Bowl against Rutgers, he ran down a wide receiver from behind for a gain of 43.

Size: 6-5, 250
Class: Senior
Buzz: Calhoun was among the top underclassmen to strongly consider an early jump to the NFL last year and opt for one more year of college ball instead. He led one of the top defenses in the nation in both tackles for loss (12.5) and sacks (eight), accounting for 109 yards in total losses. A team leader and an inspirational presence in the Spartans' lineup, Calhoun is primed for a big season in East Lansing. He's been a second-team All-American twice -- in his final college season, this is his time to rise to first-team All-America status.

Size: 6-1, 225
Class: Junior
Buzz: Is he a linebacker? Is he a safety? Who cares? Cravens is a joy to watch no matter how you define him -- a playmaking rover who can be a headache to offensive coordinators either in coverage or in the offensive backfield. Cravens dropped opponents for 82 yards in losses on 17 TFLs last year, including five sacks. In coverage, he broke up nine passes and intercepted three others. There could be some Shaq Thompson-like intrigue as to whether pro scouts see him as a strong safety or an outside linebacker at the next level. Entering his third year as a starter, Cravens will be the lynchpin for the Trojans' defense this season.

Size: 6-7, 290
Class: Senior
Buzz: From a size and athleticism standpoint, Buckner isn't unlike former teammate Arik Armstead. From a production standpoint, however, Buckner was better. He led the Oregon defensive line in tackles with 81, making 13 tackles for loss and four sacks. Buckner will be the undisputed star of the Ducks' defense this fall and is expected to draw, and effectively handle, plenty of double teams.

Size: 6-0, 197
Class: Junior
Buzz: The younger brother of 2014 Chicago Bears first-round pick Kyle Fuller, Kendall is filling his sibling's shoes nicely as one of the top cornerbacks in college football for the Hokies. He broke up a team-high 15 passes last season with two interceptions, giving him 26 breakups and eight picks for his two-year career. He'll be the best man-to-man coverage cornerback in the ACC this season and has the size to handle bigger receivers.

Size: 6-2, 235
Class: Junior
Buzz: Smith anchored the Fighting Irish defense as a sophomore last year with a team-high 112 tackles, leading the team by a distant margin of 34 stops. He played his best football against Notre Dame's toughest opponents (career-high 14 stops against USC and Stanford). He moves extremely well laterally, gets off blocks and makes tough open-field tackles look routine. If healthy, there's no reason Smith can't be a first-team All-American this fall against an always-tough ND schedule that includes Texas, Georgia Tech, Clemson, USC and Stanford.

Size: 6-4, 312
Class: Junior
Buzz: With all the sack masters to make this list, it wouldn't be complete without a burly, space-munching defensive tackle who dominates the interior. That's Robinson, although he's not to be confused with a stationary nose guard-type. He led Alabama in sacks as a freshman in 2013 and has the athleticism to disrupt the backfield. He plays a lot like former Alabama defensive tackle Marcell Dareus, who was the No. 3 overall pick of the 2011 NFL Draft by the Buffalo Bills.

Size: 6-1, 246
Class: Junior
Buzz: Wright won so much hardware last year, he probably couldn't fit all the trophies into a selfie. Between the Nagurski Award, the Bednarik Award and the Lombardi Award, all that's left to chase in 2015 for the Pac-12 Defensive Player of the Year is the Butkus Award. He amassed an astounding 163 tackles for the Wildcats last year, with 29 tackles for loss, 14 sacks and six forced fumbles. That's about 12 tackles, two TFLs and a sack per game, on average.

Size: 6-1, 201
Class: Junior
Buzz: As a sophomore, Ramsey was named a first-team All-American by USA Today, and ACC coaches named him first-team all-conference. What makes the Seminoles safety so impressive is that can be a dominant presence anywhere on the field, from the opponent's backfield to defending the deep pass. He broke up a dozen passes with two interceptions in coverage, and added 9.5 tackles for loss with three sacks as a blitzer. With new starters at cornerback in Tallahassee this fall, Ramsey will be counted on for more of a leadership role as well.

Size: 5-11, 192
Class: Junior
Buzz: As a freshman, he knocked an eventual early NFL draft entry out of a job. As a sophomore, he established himself as the best cornerback in the SEC. This year, there's not much room for improvement for Hargreaves. He is good enough to break the normal field/boundary cornerback alignment and simply shadow the opponent's best receiver, if the new UF coaching staff chooses to use him that way. He tied for the SEC lead in pass breakups last season with 13, to go with three interceptions.

Size: 6-6, 275
Class: Junior
Buzz: The dominant presence in the national champion Buckeyes' defensive front, Bosa combines the physical skills to beat offensive tackles to the quarterback using either power or quickness with a relentless motor. While he'll serve a suspension in the season opener this year, he's a big-play machine. Bosa racked up 21 tackles for loss and 13.5 sacks last year, with nearly 40 percent of his 55 stops coming in the backfield (highest ratio on team). Just how good is he? One NFL general manager measured Big Ten offensive tackles for the 2014 draft by how they fared against Bosa in his freshman season.