If X remains healthy (a big if), he should be able to play at peak level for about 3 more years (Very few CBs are top shelf after age 30)...
So the Dolphins have got to be looking at his contract and seeing that he's already signed, they know that there's no need to extend him, they've already done that.
They know that he has to play or forfeit his salary and repay his bonus money... plus fines, so anything they give him is optional... which requires that they trust him to keep his word, and to remain healthy... and since both are HUGE ifs, they've GOT to be listening to offers.
Whether we get a good one will determine our next move. That and whether X shows up for training camp or is willing to pay 50K per day to remain out.