I'm not going to tell my friend about removing him from a group project
Why don't you want to tell him about taking him off the project?
I'm afraid that if I tell him I removed him from the project it will really hurt his feelings.
I understand you don't want to hurt his feelings, but you really should be honest with him about removing them from the project. Honesty goes a long way and simple communication could make this not that big of a deal.
I'm not really a mature person though.
Even so, you should really be honest with him and tell him. He'll just be confused about the whole situation if you don't.