Whether they are holding strong at the point of attack or slicing through an offensive line and causing havoc in the backfield, defensive tackles play a huge roll in a defense's overall success.
Here are the top defensive tackles heading into the 2013 season:
LOUIS NIX III (Notre Dame): The national championship game aside, Notre Dame's defense did a masterful job as one of the nation's stingiest units in 2012. The 6-foot-3, 340-pound Nix was responsible as anyone for the success and certainly aided both Manti Te'o and Stephon Tuitt in their All-America seasons. Coach Brian Kelly demoted Nix prior to the start of the season and it lit a fire under him, as he earned his spot back and responded with 50 total tackles (the most by a defensive lineman), with 7.5 tackles for loss and two sacks. A real force in the middle of the line, Nix has the size to take on multiple blockers, plays the run extremely well, and can collapse the pocket as a pass rusher. His versatility in the middle of the line is what distinguishes him from the rest of the field and should have him on the NFL's short list come draft time.
ANTHONY JOHNSON (LSU): As a sophomore, this 6-3, 300-pound Tiger played in 13 games with three starts, but still made his mark, finishing the 2012 campaign with 30 total tackles, 10 tackles for loss and three sacks. On a defense desperate for a leader in 2013, Johnson has an opportunity to be one of the better all-around defenders in the SEC. A freakish athlete who runs like a linebacker, Johnson may just blossom into a dominant down lineman, much like former LSU Tiger and first-round NFL Draft choice Michael Brockers. Moving into a starter's role should see Johnson's numbers increase significantly.
DANIEL MCCULLERS (Tennessee): This mountain of a man spent his first two collegiate seasons at Georgia Military Academy before making the move to the big leagues. At 6-8, 351 pounds, McCullers blocks out the sun. Last year with the Volunteers, McCullers led all linemen with 39 tackles. He played in 12 games with seven starts and posted 5.5 tackles for loss. He got better as the season wore on, posting 35 of his 39 stops over the last eight games. Still extremely raw, McCullers needs to work on his technique and conditioning. However, he showed signs of dominant play last year and is only going to get better.
CALVIN BARNETT (Oklahoma State): Another junior college transfer who made a name for himself in 2012, the 6-2, 300-pound Barnett was the Big 12 Defensive Newcomer of the Year, earning All-Big 12 second-team honors for Oklahoma State, finishing the year with 30 total tackles, and a team-high nine tackles for loss, while starting every game. With a year of experience now at the FBS level, Barnett has an opportunity to excel and develop into one of the Big 12's best interior defenders.
TIMMY JERNIGAN (Florida State): The Seminoles are in need of a defensive leader in 2013, as several high profile players have moved on from Tallahassee to the NFL since the end of the 2012 campaign. The 6-2, 300-pound Jernigan is a serious candidate to fill that position. He started just two games last year, but played in 13, finishing with 46 tackles, eight tackles for loss and 1.5 sacks. Despite solid numbers, it was viewed as a bit of a down year for Jernigan, who came to Florida State as one of the nation's top recruits in 2011. An athlete with great burst off the snap, Jernigan has the talent to be a disruptive force for the Seminoles going forward.
DEANDRE COLEMAN (California): The 6-5, 315-pound Coleman continues to get better and better with each season. Last year was a tough one for the Golden Bears, but Coleman was a bright spot on the defense, posting career highs with 48 tackles, 8.5 tackles for loss and three sacks in 11 starts. It was a huge leap from his stats in 2011, when he finished with 19 total tackles with only two starts. If Coleman takes another step in the right direction in 2013, his versatility will make him highly sought-after come draft time. He has the ability to play anywhere on the defensive line and could flourish in both 4-3 and 3-4 formations at the next level.
RA'SHEDE HAGEMAN (Minnesota): Another versatile defender who could thrive in a 4-3, or 3-4 defense, the 6-6, 311-pound Hageman burst on the scene in the Big Ten a year ago, recording 35 tackles, 7.5 tackles for loss and six sacks for Minnesota, en route to All-Big Ten honorable mention. A former tight end, Hageman has made a smooth transition to the defensive side of the ball, but must continue to improve his technique to maximize his potential. The sky is the limit though for this ultra-talented Gopher.
GEORGE UKO (USC): A bit of a tweener at 6-3, 280 pounds, Uko could move to the outside in USC's new defense after excelling at the tackle position for the Trojans in 2012. Although it was a down year for USC overall, Uko made a name for himself, starting all 13 games and finishing with 31 tackles, nine tackles for loss and five sacks, earning All-Pac-12 honorable mention. Uko has an opportunity to really improve his draft stock with another solid campaign for the Trojans and his athleticism and versatility along the defensive line can only help in that regard.
EGO FERGUSON (LSU): With Anthony Johnson blossoming as a player along the defensive line for LSU, the 6-3, 308-pound Ferguson has a chance to really excel next to him. He didn't start a single game for the talent-rich Tigers in 2012 and finished with just 14 tackles, including two tackles for loss, but as one of the only players returning up front to see playing time, Ferguson will get an opportunity to shine this year. Big and physical, he could mature into a real force plugging up the middle. Johnson is much more of an athlete and will garner a lot of attention, perhaps freeing up Ferguson to have a breakout year.
KELCY QUARLES (South Carolina): As a sophomore in 2012, the 6-4, 300-pound Quarles started 11 games for South Carolina, posting 38 tackles, eight tackles for loss and 3.5 sacks. Those numbers should increase in 2013, as Quarles gets to play alongside superstar Jadeveon Clowney, who will once again command double and triple teams. A hard worker who plays whistle to whistle, expect Quarles to take the next step in his evolution as an interior menace in 2013.
HONORABLE MENTION: Danny Shelton (Washington), Leon Orr (Florida), Jeoffrey Pagan (Alabama) and Bruce Gaston (Purdue), Ed Stinson (Alabama).