I think I've asked this before, but I don't care. Why do NFL teams want Chip Kelly? He runs a very good college program that may or may not work on the fringe of the recruiting world. However, his entire system is this:
On offense, get faster athletes than your opponent and run plays as fast as you can to wear down your opponent to create space for faster athletes.
On defense, since your offense will score fast, the oppositions offense is going to spend a lot of time on the field. Consistently rotate 20-25 guys in on defense to keep your players fresh. No opposition's offenses are designed to match this, so you will usually have fresher players.
His entire system is built on outpacing your opponent with superior athletes. College football is based on good programs getting better players than their opponents. The NFL is based on bad teams trying to get better players through the draft while having as much parity as possible with a salary cap. Nothing sounds like a worse idea than taking a college coach who wins based on having better athletes and putting him in a league filled with constraints specifically designed for every team to have as equal of level of talent as possible.
