He is the younger brother of Senators Alan Peter Cayetano and Pia Cayetano, both allies of former President Rodrigo Duterte.
The state-run TV network also introduced Catherine Vital as Santos' co-anchor.
San Gabriel will be leading its new weekly segment titled 'Panahon TV Reports.'
Tulfo said he will return to the airwaves in August.
The longtime anchor of People's Television Network was abruptly fired by the management on Wednesday.