Darell Green is the 75th best player in NFL History. Redskins Blog has the video, which demonstrates that Darrell Green was among other things, really really fast.
Once of the things forgotten about the old Redskins is just how unique they were and how each brought something new to football or DC. The old Redskins had personality that matched their talent. (Unlike today's Redskins which may have too much personality and too little talent.) The Hogs changed the way that offensive line play was conducted, Dexter Manley and Wilber Marshall were wrecking balls on defense, and Darrell Green was the fastest man to ever play the game. However, as time has passed, fans and pundits have started to question whether the accomplishments of those past players would translate to today's game. The Hogs would get pushed back at the line of scrimmage, Wilber and Dexter would be effectively blocked and Darrell Green would...well Darrell Green would still be fast.
How fast was Darrell Green?
Darrell Green was so fast that when they had a competition in different events (baserunning, track, 40 yd dash) Green wiped the floor with rivals, including nine time Olympic medalist Carl Lewis. Lewis, who narrates Green's piece for the NFL Network, points out that while Green never beat him in track competitions (they ran against each other in college), Lewis points out that Green was a world class sprinter, and again really fast.