My friend has this girl who she plays sports with and this girl has feelings for her. My friend is straight but she doesn't know what to do and she thinks that she has feelings for the other girl too. She is asking me for advice and she needs help what do I tell her??

How old is your friend and the girl she has feelings for?

Being curious is normal. Finding yourself attracted to the same sex is also normal. It has nothing to do with your sexual orientation, it has to do with growing up, learning who you are, what you want, what you're interested in.

Your friend may be bi-sexual, but if she's young I'd be more inclined to say that she's just confused, doesn't yet know what she really wants.

Just be supportive, stress to her that exploring your options is okay, as long as you explore safely (no sex).

Girls, in my experience, get very curious sometimes. If it is just curiosity rather than feelings, if it's not going to hurt anyone, maybe tell her just to go out with the girl once on a sort of date thing. If it is real feelings they have for each other, then you need to tell them both to explore what they are really feeling and ask them to sort it out between themselves. If it turns out that both are gay/bi, then be supportive of them. You really shouldn't be the middle man though. If anything goes wrong at all, they might "shoot the messenger" so to speak.