What topics have you covered in your mathematical modeling and probability course? Interpolation, numerical solutions to systems of equations, estimating eigenvalues, etc? If so, I have a pretty easy topic. For the statistics course what did you cover? If you're going to do the topic you want to do you're going to need to use play by play data, not sure how much programming and scripting you know in order to compile the data. For that course you probably haven't covered anything robust enough to reinvent the sabermetric wheel. Just do something that's been done before like comparing career averages to playoffs. Nothing fancy.