Thank you master of none. I think you're right- sports in an "in" but there may be a variety of reasons why he's not making friends as handily as the other kids. I expect that his intense personality and some social awkwardness also contribute. I will explore that with his teachers.
The question is whether DS wants to be involved badly enough to spend time on things he is indifferent to or actively dislikes. My DH (sporty and "guy's guy) worries that being the odd boy out will damage DS and we should insist on some skill training so he can at least be included.
Me, a square peg myself in school, I believe that DS should do things that he enjoys and consequently, is willing to put the effort into. My opinion is that traditional sports have a short window and a short shelf life unless a child has some natural aptitude and is willing to train. I'm female, however, and may not understand the dynamics of "boy" friendships and interactions to be a good judge.
