Given that the fight's outcome was close and Donaire was defeated, they should make the rematch on this very same year as every time goes
That's the big reason already for Donaire to retire if:
- the fight went close in favor of Santiago
- the fight went landslide in favor of Santiago
No need for rematch but rather hang the gloves. Santiago is not even on the contender list but was just given a chance for a title shot. Again, as I previously said, if Donaire can't keep up with Santiago, there's no way he can keep up now with those top-ranked boxers at 118.