This happened to me a while ago, I think the game didn't register that my sim was at work. Do you still get promotions? Also, I have found that at the higher levels, you need to use all four regular days to prepare, if you want the bar to progress completely (for any who don't know, you can hover your mouse over the drop-down menu for work interactions, when you have the Prepare for Game (I think it's called, it has been a while since I've played an athlete) metric selected, and a bar shows how much progress you've made in preparing for the game).