Your freshman is at a D2, I think, but perhaps you had better double-check the D2 manual to see about eligibility, which may well be different outside of D3.
D2 and D3 can have unlimited rosters, but D2s also have scholarships, so what it means to be "on the roster" but not play is different, I'm sure, and also different from D1, where if you don't play all season, you are a redshirt with eligibility - and presumably you are practicing.