"3.
Kevin White vs. Amari Cooper: When West Virginia's White ran his blistering 4.35 second 40-yard dash at the combine, it appeared that his combination of size, speed, athleticism and potential would make him a lock to be the first wideout off the board. Particularly when it appeared Alabama's Amari Cooper ran a 4.42 in Indianapolis and didn't cut the same imposing figure.
But distinguishing the pair by pure speed became even tougher when NFL teams got official unreleased data (the stuff that isn't shared with the media) from combine workouts. In reality, both ran faster than the times released by the NFL Network. Cooper ran in the window of 4.35 to 4.38 seconds, and White was listed in the window of 4.32-4.35.
As time has gone on, Cooper's tape has helped him immensely, as well as individual workouts. One highly regarded source in the scouting community raved about Cooper's route-running in March, and said of his pass-catching ability: "You rarely ever hear the ball hit his hands." The same evaluator told Yahoo Sports that White had a more unrefined game, but also had a higher ceiling for development. He also added that White's game also revolved a lot around his own confidence: when he's on (which is most of the time), he's a terror for defenses. Conversely, he can have the occasional game where he doesn't appear as aggressive as his size would suggest.
Most still appear to believe that White's edge in measurables (2 inches taller than Cooper, with arms more than an inch longer) will make him the first wideout off the board. But that race is closer than most think, and personal workouts could tip the scales in Cooper's favor."
http://sports.yahoo.com/news/smoke-screens-around-marcus-mariota-make-him-nfl-draft-s-biggest-domino-005301737.html