Don't know if this has been specifically said in the thread above, but VT defensive back coach Torrian Gray is the best DB coach in the country. If he and Foster wanted young Mr. White, we have a fine prospective football player.
I had the pleasure of watching Gray coach during a full-go VT practice two years ago. He stands back on the side of the defensive backfield, in his fancy VT-colored curled-brim cowboy hat, arms crossed, placidly looking at the play. Then immediately he strides to the DB who made some slight error and calmly and usually smilingly tells him how to correct his play. The player is riveted to what's being said --- even if he's an NFLer to be. On the other hand, Foster is an absolute wildman on the sidelines during practice, particularly pre-snap, when he is running frantically and yelling various "discourtesies" in the directions of misplaced players. Carrot and Stick. The players apparently love it.