From NFL.COM
Analysis
Positives: Good speed and hustle to chase down plays down the line or from behind. Comes downhill in a hurry, but can change direction if the runner makes a move. Takes on fullback blocks in the hole so others can make plays. Often played as a stand-up rusher. Solid wrap-up tackler in space. Will try to get under the pads of guards to hold his position. Forces turnovers by attacking the ball with his hands after securing the tackle. Active in coverage, with the quickness to stay with tight ends and running backs.
Negatives: Has a strong safety build, thin in the legs and only adequate upper-body strength. May be a classic inside-outside linebacker "tweener." Played inside quite a bit for but is better on the edge because he lacks the strength to hold up versus NFL interior lineman. Has tight hips. Could get off blocks better to make plays. Inconsistent getting through trash inside. Must learn not to overrun plays.
Compares To: JAMES HARRISON, Pittsburgh -- This is high praise for an unknown player, but the more film scouts watch on Williams, the more they will notice he has the "it" factor. With patient coaching and in the right system, he could turn into one of the better finds in this draft. He plays with excellent field vision and awareness. Williams demonstrates the instincts to quickly track down the ball. He has the change-of-direction agility and lateral movement to string plays wide and hits ballcarriers with force, driving with his legs to push the opponent back through the rush lane.