My 4 year old's new teachers immediately noticed he was having difficulty "entering into play" when he started and are working on it and keeping me updated. So yes, I would expect them to consider it part of their job.

And after you say something, i'd do my best to try to observe to make sure they are actually doing something about it.

You should definitely say something. It is very important that kids bond. No child really wants to be alone. All kids want to have a sense of belonging. It is a little strange to me that kids that young don't automatically connect. Usually when they become teens they can be very clickish. Since you have observed the kids not really paying attention to your son and he is telling you is a good reason to approach the teacher. I would just express my concern and see if she could have some activities that would cause the kids to become connected. I also believe in time, the kids will get use to your son and will soon connect and be friendly.

Yes, I would say something. I would say what you said here, that you have noticed him playing by himself in the morning and ask them to facilitate his playing with others until he has been there long enough to form friendships. If they say you caught him at an off-moment, ask them to humor you. My 4yo also started a school this year where nearly everyone else had been last year, so I can relate.

My 4 year old is at a new preschool. All the kids in his class were at this school last year with a different teacher. They start the day on the playground, and I have seen (when watching from my car) that my son is playing by himself and all the other kids have friends with whom they play. I saw this morning my son try to engage two boys with not much luck. The teachers are standing around talking to one another and not actively playing with or trying to engage the kids in play.

At our old school the teachers would facilitate games with the kids to get them playing together (like tag, or other games). I thought that would be the case here, but it seems like they just watch the kids to make sure they are safe.

When I have asked the teacher how he is doing she has said he is doing great and making lots of friends. When I ask my son he says he isn't playing with anyone. Should I say something to the teacher about my concerns about the playground? How should I say it if I say something? I don't want to come off as the complaining parent.