Where exactly did that "source" get their info from? There is absolutely NO WAY that Def Jam didn't know about the remix, hell the public knew about the remix. More than likely def jam owns the masters to ALL of Rihanna's material, so she couldn't even release the song to the public without their co sign. The song basically belongs to them and they have massive control over the "distribution" of the song. And someone posting above was absolutely correct, Roc Nation has this remix mentioned on their twitter, so the whole "Jay Z wouldn't allow this " angle is moot.

BTW, Birhday cake remix ( # 1 song on he countdown that i heard) is already on the radio here in Vegas which could NEVER happen without Def Jams consent....period.