It's a much easier decision to come back for another year when you are 20-21 years old and could really benefit from another year of physical development before turning pro. At BYU, a junior is typically a 23-24 year old who has his age being held against him by NFL evaluators. Bama also has the strong lure of coming back to realistically play for something important--like a National Championship, SEC Championship, Heisman, etc. BYU does not consistently offer the same opportunities to play for important titles.