NFL 401K Plan – Rollovers Not Allowed?

My boyfriend used to play in the NFL and still has his 401K with them. He wants to rollover the funds into an IRA, so he has more control over fund choice, etc. I have talked to them multiple times, and apparently they don’t allow any movement of money at all until the age of 45. I thought ERISA requires organizations to allow 401K rollovers after an employee leaves? Does anyone know anything further about the legal issues surrounding this?