40 yard dash of 4.41 at the NFL combine.
Jamaal, as a college junior (or after his sophomore football season) ran an 11.10 in the 100 meters. If he gets his speed back (no reason he can't even after the knee surgery) I think a 4.45 is well within his ability.
Based on what we've seen of him, he has the speed and size for the NFL. Of course, if he never fully recovers, he will lose some of his ability. But if you're looking at him playing before his injury and saying based on that he's not fast enough, I think you're very wrong.