I have coached my son since he was 4. He's seven now, he started soccer and baseball at 4, basketball at 6 and golf this year. When he was 5, at least half the parents/grandparents were on the field with their boys. It would have been better if ALL the kids' parents were on the field with them. ANY coach of kids this age would absolutely welcome any parent who wants to help out with coaching the team or just their own child if that's the case. You SHOULD be there to throw the baseball or kick a soccer ball with him not because he's shy but because it is good for him and you.You may also need to assess your son's physical abilities. Age five is when kids do begin to develop the ability to master certain skills and to be able to grasp team sports concepts. However, not all kids develop at the same pace and your son may find it more difficult to master certain skills. Don't let him get frustrated, just keep playing with him and MAKE IT FUN! The YMCA teaches their staff about AGE APPROPRIATE ACTIVITIES. This means that most kindergarteners don't have the motor skills and coordination to play golf (nor attention span) and 4th graders would be bored to death playing Duck, Duck, Goose. (I was a Y councelor decades ago)As for the shyness. Make playdates with other boys parents and have them play together. They may not play "together", kids at five may still play in parallel to each other but that's okay. You can also introduce soccer or basketball in playdates but make it fun and don't just sit on the side. You need to initiate playing by kicking a soccer ball to the other mom or get a miniture basketball hoop and start playing. Both boys will likely join in as kids love to beat their parents at anything. Pick new kids that your son doesn't know well, ask a parent on the team to schedule a playdate. Take you son out of his comfort zone a piece at a time and he'll begin to open up more. If you allow him to remain in his comfort zone only playing with kids he's known since he was born he may never be able to break his shyness. I don't know what his dad is doing but he should get involved as well.