My bad I missed him. TBH I don't know a ton about other teams' young prospects/players. I knew Walker was bad defensively but I didn't know his defense was so bad that moving him to DH actually increases his value. That's generationally bad defense to the point that Zips thinks he's about a 1 WAR player moving forward.
And the list doesn't evaluate players in that way anyway. "Taking everything about a player into account, which players would garner the highest trade value, from any team, if every team viewed players the same way I do? It’s not the average value that each team would assign each player based on their respective competitive windows; just like real trades, in this hypothetical list, there’s a highest bidder, the team most motivated to acquire someone’s services."