Salazar is likely the one who agreed to let Hasay drop Boston. She is ready to run well, and she realized Boston was not the place because of the weather. Hasay will likely target another marathon to run very soon. Maybe London.
Salazar likler told Rupp to stop at mile 19. Rupp will not recover and run another marathon for a month. If no other marathon is run as a make up for Boston within a few months then the next will not be until Chicago, or New York.
I don't see Salazar letting Rupp run a marathon outside of the US. I do see him being okay with Hasay doing that.