Demar Dorsey, a safety who committed to FSU before switching to Michigan on signing day, doesn't have the grades to get into Michigan (Michigan won't budge on their academic standards-- nice vote of confidence for Rich Rodriguez), but is qualified under NCAA rules. He is now looking elsewhere, including Florida State.
A recruit who is NCAA Eligible, but who is denied admission by a school, may immediately play for another school. (This has happened in the past at UVA and Alabama).
FSU does have one open scholarship for this term by my count. I do not know if FSU would take him and have not spoken to anyone from FSU about this. Dorsey has some off-field issues that FSU must also consider if it were to take him and I do not think it would be an easy decision either way, assuming Dorsey wanted in.