I'll add that the big hurdle is between zero friends and one *real* friend. It sounds like your son does well socially, but isn't finding the deep connection with someone that he desires. That's a common problem for GT kids. Finding one person who "gets" you makes all the difference, and having lots of acquaintances doesn't fill the same need.
I confess, that's one reason why I'm skeptical of sports as a big social help. Other than giving a GT child exposure to more people--which as Dottie rightly notes offers more chances to find other GT kids--I don't think sports tend to be wildly useful opportunities for making good friendships. They're great for other things: giving GT kids a chance to work at something, teamwork, "stick-to-it-iveness," etc. And certainly there are some good friendships that were forged in sports, but I don't think of sports as terribly fertile ground for those *deep* friendships that GT kids crave.
I'd be looking for one or two kids who really get your son and he them. Even if you don't see the other families all the time, if your son has the experience of clicking with someone, it will really help him, I suspect.
FWIW...
