This might be able to help, I run into the same situation with white wedding dresses and black tuxes. I'll assume you're shooting RAW, and can use the Recovery/Fill Light sliders to help fine tune the final exposure.
Spot meter the black uniform, and then the white one, and count the stops in between. Depending on the lighting in the stadium, you'll find they are usually 4 stops apart (As long as you don't meter from the shadows). Take a reading off the white uniform for your starting point, and overexpose 1.5 stops
. As long as they are 4 stops apart this will put the lighter uniform safely inside the right edge of the histogram, and the darker just past the left edge of the histogram.
Thats always worked for me. I look forward to seeing your next set