ICOT, it’s a good idea if they’ll listen. In my experience they hear what you say, agree full heartedly, and announce that a ‘certain’ boy had a problem, and everyone knows exactly who he is talking about.
I don’t know if a better ball will make more popular. It probably won’t. It has to do with his personality and self image. Some are born to be popular in certain ages, others for different ages; some in all ages and others in none. As the children mature and different skills are needed, different boys shine and rise. Just wait it out.
To help him deal with it now you can point out that it is wrong to leave people out and there is nothing wrong with him. Give him an interesting book or project to keep him busy during recess.