I was going to suggest the same thing, have the friend involved in the sport in some other way - team selection, scoring and umpiring etc etc. Have they just started at a new school or are they in Grade 6? Starting at a new school will make it harder, but if he is with many others that know him and know that he was really into sport perviously may make them (the other kids) want to help out too...

I also just want to congratulate your son on being such an AWESOME little (big) man - so many kids will have have ditched their friends. It cant be easy on your sons friend either, having someone that is willing to stick by him must help alot - he must be finding the adjustment so difficult, not just physically, but emotionally too...

Good Luck, this will be a difficult time for your son as he will feel so torn between wanting to go and have fun and being loyal - his friend will know this too