I've seen a lot of social media chatter with Husker fans upset about no longer being able to attend the game on Saturday. I'm sure you're not alone. Unfortunately for many, Saturday/Sunday games are the only time they can attend (especially those who don't live in or near Lincoln).
Now it had better rain on Saturday!
I can say the best chance of rain/thunderstorms in Lincoln is Saturday night. It's not a guaranteed rain during the daytime. Chances will increase during the afternoon, but better chances east-southeast of Lincoln until night. But I understand, as it's too close of a call to risk it. And I doubt Sunday was an option, as it's likely Michigan has a plane scheduled to depart well before that.