During the offseason task "Leaving Players" of your Dynasty, you will have the chance to convince your players to stay for another year. Simply click on any junior (JR) that is planning on entering the NFL Draft and pick the "Promise the player he will not regret staying to get his College Degree" option. Players' thoughts on staying on the team may vary, so make sure you convince a player that has a green status under their name.
Achievement will unlock after convincing the player.