Right now I think Realmuto would net more in a trade than Machado. In a vacuum, I would pay more for 2 1/2 seasons of a 4 WAR catcher than I would for 1/2 of a season of a 6-7 WAR 3rd baseman (and especially so if he insisted on playing SS, where he is far less valuable defensively). So I think Allard as a centerpiece for Machado is probably more realistic than Allard as a centerpiece for Realmuto.