Since the beginning of fourth grade, there's a boy who's been very competitive with my son. He has since formed a clique to make sure my son doesn't get picked for any school teams. Consequently, my son has been all but ostracized at school.
I think jealousy might be a factor. Should we change schools?
The school's physical-education teacher could be especially helpful with this problem. Most PE teachers and coaches use alternate methods for choosing teams (by birthdays, by letter of the alphabet, etc.), and the children could be required to use them on the playground as well as during PE class.
You could be correct in your assumption that the other boys are jealous of your son. Changing schools might be a solution in the short-term, but that is a drastic course of action and may give your son the message that he should simply leave when things get tough. Talking with the other boy could only make things worse.
Is there any way to encourage your son to develop other friendships? Perhaps he could become friends with boys who are not as athletic and focus on other strengths, such as computer skills or art. Or perhaps there are some boys he knows from your team who go to another school who could be invited to your house to play. If the other boys are excluding your son to be mean, making friends with other children would take the power to hurt your son away from them.