I just tweeted him and he responded within 5 minutes! He said that both women's volleyball and soccer teams prefer to play at night, even when the football team is playing. Seems a silly choice by the soccer team to me given that they could simply move it from 6pm and 5pm to prevent the conflict but I guess that is their call.

I don't like the answer but I really appreciate his response to what I am sure is a common question. Amazing to me he makes himself so accessible and is so responsive!