So Damarius Bilbo ran about a 4.7 in the 40 at the NFL combine. Will that hurt him? Well, absolutely in terms of draft position - or getting drafted at all. Will it preven him from getting his shot in the NFL - probably not, as this mention attests:
Receivers who may have hurt themselves with their Combine showings included Mike Hass of Oregon State (a 4.59 40), Damarius Bilbo of Georgia Tech (4.7), Pitt's Greg Lee (4.59) Skyler Green of LSU and Brandon Marshall of Central Florida. Still, there’s more to playing wide receiver than sheer speed. TheNFL is full of "possession" receivers with similar 40 times.