If my son were a gifted running back I'd council him first to be grateful for his gifts. If he was good enough to play pro ball at a high level and wanted to bad enough, I'd encourge him to "Go for it!"
I'd also advise him to take a wise and informed look at what he would be getting into.
"Take a look at Earl Campbell," I'd tell him. "Not all former backs wind up pushing a walker for the rest of their lives, but most leave the game with - and partially because of - bad legs. When you're forty and have sons of your own do you want to be able to hunt and fish with them, like we do? If you go in, go all in - and know when to cut it short. A running back lasts typically for four years and gets paid less than the other ball-handling positions. Know what you're getting into - assess it along with with all of your other options and if this is an opportunity you don't want to pass up, I'll be your biggest fan. If you decide to pass it up, I'll still be your biggest fan. Don't ever forget that."
"You'll be on a big stage. The way to play your part will be the way you've always played it - give it your best shot, with all you have to give. I raised you to be a man of your word, a man whose character counts, and I'm proud of the man you've become. We all stumble and fall every now and then, but keep getting back up - no excuses - what we are living up to, and how hard we try to live up to it, is ultimately what we are measured by. Look at Lawrence Taylor - great football player, whose reputation slipped quite a bit when it was learned that his level of play was enhanced and he was a 'roided-up, coked-up junkie who happened to be playing football instead of living on the streets. He paid for it. You know better than that. Don't make those kinds of stupid mistakes."
"Surround yourself with good people. Among them, get a good agent. Study the field - don't sign with the first guy who approaches you; YOU choose the agent. And if you sign as a back, know the bigger risks for comparatively lesser rewards going in. Don't let resentment or jealousy sway your decision once you've made it. And when you sign, live up to your contract and earn every penny. I've raised you to be a man of your word. If you decide you want out, want to be traded or whatever, do it right. "
That's what I'd tell my son. That's what I told my two grown sons, in different terms but essentially the same batch of messages, as they grew up and chose their own paths. They've both grown into men that I'm proud of as a father and am proud to call my friends in addition to being my sons.
Back to my hypothetical running back son: Neither of my boys would call me about participating in a wildcat strike to see what I'd have to say. They'd know that they'd get an earful - "You signed the contract knowingly and willingly, and if you play it right you've got a multimillion dollar jump on life, regardless who's making more money than you are. If you want to change the way contracts are written, or free agency, go through the players union. If you want to see rules changes, or whatever, there's a right and wrong way to do things. Walking out on a contract you signed and are obligated to, a contract that affects the other parties as well, where people are rightfully depending on you to live up to your end? Wrong thing. You know better than to ask me. That's not the way I raised you, and deep down, that's not the way you are. Now suck it up and deal with it."