Either way, individual or team sport... it will be a learning curve for him... in learning about sportsmanship and all the good stuff... which he does not have totally 'mastered' yet.
I also read a CNN article that sports like Football... over time... can cause brain damage.
Here are the links for the articles:
http://www.cnn.com/2009/HEALTH/01/26/athlete.brains/index...
http://www.reuters.com/article/idUSHAR36644720070723
So, you might want to consider these aspects of it... and the fact that a young child's brain is not even fully developed yet. The human brain not being 'fully' developed until 26 years old.
Next, a 'sport' like Karate etc., might be a good option for him. It is an individual 'sport' but yet... it teaches 'attitude' and discipline. There is no room for 'bad' attitudes in these types of 'sports.' They teach the physical skills AND the 'character' of the person.
My daughter takes Karate and LOVES it. They do not keep "score"... but it is about the individual's self-development... and skills... in conjunction with treating others with 'respect' etc. And the benefit to all this, is the child learns how to defend themselves AND about self-control. Discipline.
AND in Martial Arts... is does NOT matter how 'small' or 'big' you are.... it is not about 'size' of the child.
In my daughter's class for example, there is a very small boy for his age... and he is one of the best as far as capability and discipline... AND even against much bigger kids.
Next, with sports like football etc., where the emphasis is on 'winning' and 'keeping score'... is that what you want him to focus on? A 'score' is not always the best learning tool... to improve oneself or to 'define' a person's real worth AND character.
As the other poster said as well, Fencing is a GREAT sport. My Hubby and my daughter did that. It teaches great character as well... and skills. Not just it being about keeping 'score' and who is better than the other.
Decide... what you want your son to ultimately 'learn.' Would it be about developing his 'character' and self-discipline... or have him just learn about being better than another based on "winning" or 'scoring' in a game???? Some kids for example, only base their confidence or self-worth on what 'score' they got. Versus on their own self-worth and sense of self and identity.
Discern... what you ultimately want your son to learn... and how you want him to develop, as a person.
This would be my suggestion.
All the best,
Susan