Pulled hip flexor? Game on Monday!

I think I pulled a muscle in my hip going for a fly ball and kind of twisting around funny. I think it’s my right hip flexor, kind of towards the back, and it’s uncomfortable to walk or put weight on my right leg. Stretching doesn’t hurt, but I don’t think it’s making it feel much better. I have a game on Monday, so what are the chances of me playing in that? Going through the pitching motion doesn’t hurt, but I can’t run. Do these things clear up quickly most of the time?