Here is something football fans are not considering. As long as you passed your grade or went to summer school, you can play football. Since football will be later your going to find that some pretty talented kids are not going to qualify when the season begins.
Not knocking anyone's intelligence, but it takes a pretty good amount of kids to play football. Another thought is do some kids want to play during the cold (Going outside during the summer and spring is fun).
Also the D1 recruits like to get to college early, if you already have an offer, is it really worth it to play this season, and turn around and be on a college campus this summer?