Well, the Twins haven't moved Sano off third yet. And I don't know why you'd move Plouffe off third since his improved glovework is half the reason for him being a top 10 3B now. And where would you move him to? That is the whole conundrum with hoarding all of Plouffe, Sano, Varags, Arcia, and Mauer (who has a NTC). At least one player would have to move off position which automatically squanders value right there.
A trade could easily be the more efficient option IMO.