Cahill said: "I didn't want to bring Everton here and have all the kids playing - not to disrespect them but I wanted to have the main players and show respect to the people that are coming to watch the games.
"The manager has been really focused on how hard we train. It has been non-stop training. Everyone has been saying 'can you show the lads the city?' but I don't think we've got time.
"This is for us to get fit, not to have a good time."
Cahill will feature against the A-League newcomers at AAMI Park but Moyes will carefully monitor his involvement.
Moyes told the club's website: "I'd have preferred Tim to make sure he had a good holiday.
"We've not asked him to train, just a little bit before the game to keep ticking over.
"I've just got to make sure I don't feel the effects of Tim having no holiday in six or seven weeks' time."