You don't trade pieces of value for a backup catcher. If our backup catcher is a starter on another team then that team will trade accordingly. If only one team wants Castillo then yeah, sure, the Cubs can get lowballed and be stuck with that or nothing. But if more than one team are interested, one of them is going to have to pony up more than the other. Castillo, as a lefty masher at catcher, holds some value. No one is going to give up top prospects or players for Castillo straight up, but packaged with the right players in the right deal and he could be useful in getting something good in return. Also, pitch framing aside, Castillo ranked as one of the top defensive catchers in baseball last year. He's also one year removed from a 3.3 fWAR/4.5rWAR season and has put up 5.5 fWAR/6.3 rWAR the past two seasons. Just because the Cubs aren't interested, doesn't mean no one will want him. Just because that's what we would offer in a 3-team deal does not mean he's the centerpiece in a 3-team deal. Unless I'm interpreting TT wrong, in this example "centered" does not mean he's the centerpiece, just the piece you start and work to build a reasonable package with. Seems pretty obvious that's what he was going for, though I could be wrong. Because you claimed Castillo is replacement level (based solely on pitch framing ability and nothing else) and therefore holds zero value, I used another replacement level player to show you that's not true. Not that difficult to figure it out. Also the defensive metrics that bog down Kemp's overall WAR value are the same ones that show Castillo was the 4th best defensive catcher in the majors last year. His 32.9% of runners caught stealing would be 3rd best in the majors among qualified starters. So really despite a lot of defensive metrics saying Castillo is actually a good defensive catcher, because he's a poor pitch framer you are immediately writing off any value he has whatsoever because you apparently seem to think all 30 teams in baseball value pitch framing the same amount as the Cubs, which isn't true. I don't think he has a ton of value, but I think he's a good complimentary piece in a multi player package.