You have no idea how your body works. None. You wake up each day for reasons you don't understand, eat things you can't name the ingredients to, drink beverages you can't make yourself, and then pass out at an appointed time you can choose within certain parameters. (Like it or not, even Pete Carroll has to literally lie down for hours at a time like an unbelievable pussy. You do it for eight hours a night on average, you simpering mollycoddle.)
It's probably for the best that you don't understand how it works. Percy Harvin is the cautionary tale of going down the rabbit hole of anatomical connections, where you discover that the heel injury is connected to the knee, to the hip, and that if you so much as breathe on any of this incorrectly, it gets huffy--nay! Insulted, even.
"The bottom of the heel is filled with tiny honeycombs, lobules of fat and muscle that absorb shock. You have insulted those during surgery, so you're not going to be able to bear weight on it the same way right away."
In retrospect, our calling Percy Harvin's heel "a fucking asshole" two years ago may have been a tactical error. We apologize profusely. On the upside, if Harvin jukes left against Tennessee and his head explodes, you'll now have a very tangential and vivid illustration of how everything in the human body truly is connected.