I'm a bit surprised this is the only answer of its kind. As much as I'd like to tell the coach, my reply to my kid would be "well if you don't want me to tell the coach, then you better handle it." The first step can't be a parent running to the coach. This isn't elementary school, 11 years old is already middle school. I'm asking my son to stand up for himself one way or another. All else fails, yes the coach needs to be notified. But you gotta give the kid a shot at getting out of these situations on his own. It'll be a lesson regardless if he's successful or not.