IF Viz has more value as a trade piece than a long term closer for the Braves, then he should be moved. Problem is, that is a subjective valuation. There are some, me included and maybe foremost, who think that having a closer of any type right now isn't of much value and, if he can bring back multiple long term pieces who fit long term needs and have better overall talent value, he should be traded. Even if you believe that he is a high end closer who will provide that value over the next 3 or so years (I don't), he still will increase dramatically in cost as a true competitive date approaches. As his service time increases and his cost increases and his FA date approaches, his value declines.