I was thinking about making sure that her equipment, isn't the problem, too. Cleats can be washed. If you don't want to throw them in the laundry, a bucket of hot soapy water will do it. If you need to, throw away the insoles and get new ones.
Check the glove for odor. There should be none. I have worn a microfiber sponge in mine before, to soak up dirt and grime.
Check the batting gloves and launder, those.
And don't forget my post where I washed my bat bag at the car wash.
I would buy her extra sports bras and sliders, and let her change, as necessary.
It's just her arm pits that smell. She sweats on her back some too...but the odor comes from the arm pits. It is Arizona...but I don't want her embarrassed. Thank you.