The issue here is the team. It would be one thing if it was just schoold or similar, but we are talking about a team of 12 girls that need to be able to work together to be successful. She can't just hang with the girls she gets along with. Otherwise I would let her work it out.
We did have a conversation similar to what you said...standing up for yourself. The funny thing is she is the girl that steps up when another person is being teased or not be treated well. My husband was approached one day by this one man we know. He told him how our daughter stepped up for his stepdaughter .. she was being treated by her friends in a very mean way. My daughter heard and went and approached the girls that were being mean and basically gave them the riot act. Then had this girl come sit with her and her friends. We had no idea. This step dad is a high school basketball coach and has offered giving her some help in her skills as a result.
Any way I pointed out that I cider and asked why she doesn't do the same for herself. I told her she us worth it. I told her not to be mean but to confront it. And gave her examples how to approach so it isn't mean but direct.
In either case this weekend games club girl was very nice to her so it appears her mom spoke with her. I think in this situation parents and the kids are invested in the team so the dynamics are different.