I saw the following quote from Miles about not likeing to practice with helmets only. If he doesn't like it then why are they doing it? Is it a NCAA rule for the first 2 days or something?
I think it's just to gradually work them into practice. You don't want them going all out the first couple of days.
After the recent run of serius heat related injuries and deaths over the last ferw years, the NCAA basically told them how many days they have to go before they can suit up in full gear. If you remember the NCAA sent members down to Baton Rouge to watch Saban's practices because he did it this way. They basically followed his plan and made it a rule.