The way most D1 schools run their programs, in the fall is when they break freshman down. I know that sounds harsh but the idea is they want you to start over and learn their system. You will go down there and learn a bunch of bunt defenses and pickoffs and all kinds of situational things that will make you feel like you're way behind but trust me EVERYONE goes through that in college. The biggest thing I can tell you is to get yourself in shape with a good running program. Really thats the only thing you can honestly prepare for because most coaches understand that when new guys come in they are starting all over and thats perfectly okay. Good Luck.