Kyle Williams is their NT. There is no reason Kyle can't be succesful. He has been a starting NT at a high level for 4 years. He has the build, short/stout, and motor that you look for. I'm sure the argument will be that he is not a 2 gap player, however I have yet to see that they will be running a 2 gap system.
The major issues with the defense last year was the amount of time they were on the field. They need oline and offensive playmakers. If the tackles are gone draft Clausen or Spiller.