Henry is dangerous once he gets to the second level.
In the NFL, he's not gonna have the humongous holes to run through and pick up speed like he has at Bama.
Unless he gets picked by the Cowboys or Panthers, which both have schemes that run the ball downhill, he will be average.
Even then, NFL defenses are so big and fast, he would have a hard time shining.
This isn't the NFL of the late 70's and 80's, where Earl Campbell and John Riggins were bigger and faster than a lot of the D players.
Nowadays, NFL defenses are full of big, fast players that'll knock a fool out.