I would certainly not move him for peanuts but would not cry if he were to be included in a deal for a SP.
It's not a matter of disliking Mateo for me, quite the contrary I respect the hell out of the work he has put in to improve his offensive game. I just think his value has substantially improved, he plays a position of organizational depth, and would I would not lose my mind if the team moved him to improve the rotation. That said, will be happy also to see him on the roster at the end of the season.