Per Steve Pivovar at the Omaha World Herald, tonight's game between Missouri State and Creighton will be played as scheduled. There has been perisistent rain in Omaha over the last 24 hours with more scheduled through tomorrow evening. He stated that TD Ameritrade Park can take on lots of rain and it sounds like it has.
If the game cannot be played tonight or tomorrow, I'm not sure if they will play on Sunday or not. I would guess not considering both teams would be wary of over utilizing their pitching staff during a Sunday doublheader with the league tournament starting on Tuesday.