Soon this file will change, as it'll be top prospects broken down by whether they're in the draft or returning to school, but for now it's still about juniors and seniors. As anyone who follows the NFL draft knows, many of the top prospects in the draft come from the junior class. The first round will be dominated by underclassmen every year. The majority of players on my latest Big Board come from this group.
For the top junior and senior prospects together, make sure to check the latest Big Board.