It's just a player saying "We'll take you on our team."
Put yourself in Stanton's shoes right now... a sinking feeling of desperation and depression. Loria needs to make him happy to be with the Marlins. A requisite first step in that process is resignation: Stanton needs to be convinced that he is stuck there - no way out. Any encouragement that there is a way out runs counter to that process. A Nats player saying "We'll take you on our team" just encourages him to want to get out.