No one ever wants to part with what could be a future hall of famer for a temporary piece. The Houston Astros have been on the good side of that receiving Jeff Bagwell for Larry Andersen straight up. They’ve also been on the wrong side of it trading Joe Morgan who would go on to win two MVP awards in back to back seasons with the Cincinnati Reds.
But prospects are just that. Prospects. The major league player you’re trading for has a track record. You know to a certain extent what you’re receiving. Hence multiple prospects being sent over for just this one player because you have no idea how prospects will do once they face off against the top talent in the game on a daily basis.