The numbers: 6043/300/5.04
2006 stats: 2 tackles, 5 assists, 1.5-1 tackles for loss
The player: Before the 2006 season, everybody expected a dominating year from Harrell, but a severe bicep injury basically cost him his senior year.
When he's right, Harrell can be dominating against the run. A big, thick kid who's much stronger than he looks, Harrell is very effective at clogging up inner run lanes and forcing teams to run around him rather than challenge him. Although he could do a better job at anticipating snap counts, he has natural explosion and because he keeps low and has outstanding leg drive, he is very rarely beaten on the first step. Hard to handle one-on-one, he gets into the backfield regularly and delivers a massive punch when he arrives. This guy could teach tackling technique for a living.
While he can push his blocker back into the quarterback on occasion, he doesn't have any pass-rush moves more complex than that and will be less effective on passing downs in the pros than he was in college. Even on run downs, much of his game — though instinctive — is primitive, from sub-par hand usage to a tendency to be taken in by trap blocks.
Still, he's an intelligent and emotional kid who plays extra-hard from snap to whistle, so he is very likely to improve in those departments. But while he may well become Xs and Os smart, I don't think he'll ever develop NFL-quality pass-rush skills.
Keep in mind that the bicep injury he suffered as a senior wasn't the first ailment that caused him to miss games in college. His durability is a lingering question that will have a definite impact on his draft status.
Reminds me of: Harrell's a lot like the Ravens' Dwan Edwards, a second-round pick in 2004 who does a lot of mostly thankless work as a run-stopping end and comes out on passing downs.
How he fits: The Colts would throw Harrell into the tackle mix and expect him to contribute right away. The team continually rotates its defensive linemen and would make an effort to get Harrrell in the lineup on first and second downs to help seal up the all-too-porous middle.