I'm really unsure what I'd do here. On the one hand, polanco is still a real hitter and can play second and third. He's really a good hitter.
On the other hand, this is exactly the kind of guy you trade to build a deep team for the long run. There are others that play his positions, and he's on an expiring deal. The exact guy Tampa turns into other assets every year.
I lean, slightly, to trading him for prospects. But if they keep him, I'll not be even a little unhappy. The rare time I'm not sure there is a bad decision.