Barry has slotted seamlessly into the Toffees' midfield since his loan move late in the transfer window, but he is ineligible to play against his parent club at the the Etihad Stadium.
It is a match when the former England international's vast experience would have been in demand, but Martinez is keen to focus on the positives and how the Barry effect has filtered out to the rest of the squad, particularly the impressionable youngsters.
"There has been a lot of talk about his 500 appearances in the Premier League (chalked up in Monday's win over Newcastle) which is an incredible stat and shows the experience he has," said the Spaniard.
"But the way he is as a human being is an incredible influence for players like James McCarthy, Ross Barkley up to a point - players who can look up to someone who has been through many experiences and can give some sort of calm influence.
"On the pitch I thought James McCarthy developed a good chemistry with Gareth.
"In the second half against West Ham he did that straight away and he grew even bigger against Newcastle.
"Players like James and Ross are going to get stronger and better and learn so quickly from someone like Gareth - he adds to the development of our youngsters, which is invaluable really.
"I was always aware (of his ineligibility against City) so we need to accept it will be a period when he can recover, have a breather and get ready for the next game.
"What matters is not that you are going to miss with Gareth, it is the opposite: (it is) what he is bringing already and the influence he has had in the dressing room and the games and how excited we are to have him for the rest of the season.