1. Iowa State: The Cyclones top the list after a huge year from their outstanding duo, Jake Knott and A.J. Klein. They combined for 231 tackles in 2011, both finishing among the top four in the Big 12 in tackles. They had 241 together in 2010, but this season Knott played through injuries and Klein was awarded co-Defensive Player of the Year honors from the league's coaches.
2. Texas: The Longhorns will sorely miss an outstanding duo of their own with tons of experience. Keenan Robinson and Emmanuel Acho are both NFL-bound after combining for 215 tackles.
3. Oklahoma: The Sooners weren't quite as good as expected in 2011, but part of that was because of a Travis Lewis preseason toe injury that slowed him for much of the season. Lewis, Tony Jefferson and Tom Wort all topped 70 tackles in 2011, and are a solid group.
4. Kansas State:Arthur Brown reinvigorated this group, finishing eighth in the Big 12 with 101 tackles, but the Wildcats linebackers were more than just Brown. Tre Walker and converted safety Emmanuel Lamur combined for 135 stops and helped lead one of the league's most underrated units and a much-improved run defense.
5. Texas A&M: The Aggies' backers were big pass-rushers, though they struggled in coverage this season. Sean Porter was the Big 12's sack champion with 9.5, and Caleb Russell and Jonathan Stewart combined for six more. Damontre Moore is the rawest talent of the bunch, but built on that in 2011, making 72 tackles.
6. Oklahoma State: OSU's group was good, but not great. Alex Elkins' crazy story came to an end with 90 stops in 2011. He showed up everywhere for the Cowboys, but reigning Big 12 Freshman of the Year Shaun Lewis didn't quite have the sophomore season some had hoped. Caleb Lavey added some solid play for the turnover-hungry unit, producing 74 tackles and five tackles for loss.
7. Missouri:Zaviar Gooden wasn't quite the impact player Mizzou had hoped, but he was solid alongside a group that's been injury prone over the past two years. Sophomore Andrew Wilson emerged as the team's top tackler with 98 stops, and Luke Lambert added 82 more. A high ankle sprain in the season opener kept Will Ebner off the field, but he'll be back in 2012 after the NCAA granted him a fifth year of eligibility.
8. Kansas:Steven Johnson led the Big 12 with 119 tackles, but the rest of the unit left a lot to be desired. Darius Willis has some potential, but the rest of the team's linebackers have their work cut out for them in 2012. Tunde Bakare also returns from a unit that ranked ninth in the Big 12 in rushing defense.
9. Baylor: The Bears needed help just about everywhere. Elliot Coffey was solid, and finished tied for fourth with 114 stops, but Baylor was eighth in the Big 12 in rush defense. Baylor has solid athlete in the secondary and on the defensive line, but at linebacker, Rodney Chadwick and Brody Trahan leave a bit to be desired. Ahmad Dixon was better in 2011, but still has a lot of potential that needs to be filled.
10. Texas Tech: The Red Raiders are looking for a new defensive coordinator and the 4-2-5 made a short stop in Lubbock. The Red Raiders were awful everywhere on defense, but especially up front. Nobody in college football was worse at stopping the run, and D.J. Johnson, Daniel Cobb and Cqulin Hubert turned in forgettable performances. Time to get better for 2012.