Ok let's broaden this question. I've already expressed my doubt in the previous response. Let's assume this guy really is that good. There's a chance that this happens all the time in other sports. So, what about other sports?
At a certain point there should be a clear difference between their potential and their actual achievements bc being a pro athlete isn't necessarily easy work. I would love to play a big 4 sport, or other common sport instead of my 9-5. But, there's plenty of people that wasted their talent and took the easy way out by not competing. Maybe they didn't have the work ethic or discipline to stay focused to a sport. Also, It appears that everybody was "good" when they didn't actually compete. And, the older people get...the better they used to be. It's prob some psychological phenomenon. Until somebody gets out there and proves they are legit that good, I'll always have a little skepticism.
That said, I'm sure to this day there is talent walking all over the world with people full of potential or once full of potential. Is Rusk one of those guys? Maybe. I know guys I played sports with in middle school that were outstanding athletes and excelled at most sports. But when they got in high school some just dropped out (some of the best ones) or couldn't stay out of trouble. This is specifically true for my high school football and baseball team who could of used some of that talent and took a good team to a great team. I realize sometimes the talent gap fades away as you get older and move up in competition.