I've seen disabled children on the team but not a part of competitive play. Usually there's an exhibition play or two where the disabled child gets to play. For example, a disabled child is given a basketball and shoots until it goes in, but the basket does not count towards the score. It doesn't take much time, the kids on both teams are happy to do it, it teaches them something about humanity, and for the disabled child? It means everything. For the parents, too. Good stuff.