I think that is a big overpay on the Brewers' end. Castro's contract almost gives him negative value, and Yelich and Realmuto have asked to be traded, reducing the Marlins' leverage. I would be more inclined to say Yelich/Realmuto/Castro for Arcia/Pina and maybe Broxton or a lower-level prospect like Supak or Ponce. Major league players carry a much higher value than prospects. Castro's owed just under $23M over the next two years. For a 1-2 WAR, maybe even 3, 28 year old that's almost chump change in todays' game. And it's only for 2 years.