This is all moot because he's not being traded. But if he were, yes you trade Castro if you have to, and no Rizzo to Stanton is not in any way a lateral move. Baez's ceiling is to be almost as valuable of a hitter as Stanton already is. If you think the injuries will be an issue, I get that. But to set them aside for a moment: Age 22 season, fWAR normalized to 162 games played: Stanton: 7.2 Pujols: 6.2 Bonds: 6.0 A-Rod: 5.3 He's an MVP quality hitter, and he's still younger than three of our top 10 prospects (using the FG list). We don't have anything in our system that compares with him.