If he would sign that deal you outlined the Twins should do it. You can buy three years of free agency now. If you wait until he is a free agent the contract will be much longer. I would sign Sano, Berrios, Rosario, Polanco and Kepler also. Just because you sign for long term does not mean a player could not be traded. In a some situations the cost certainty is a plus and adds value. You could lock up this core for 7 seasons. Go for it.