Foden has appeared twice off the bench this season and played 26 times for the champions last season.
The 19-year-old is expected to kick on again this season, but the boss says it is not easy to accommodate everyone when he has a fully fit squad.
Asked when the youngster might start this season, Pep said: “I will decide when. I don't know when, but it will happen as we could again play an incredible amount of games.
“I love this guy, but at City we have Kevin De Bruyne, Bernardo, David Silva, Ilkay Gundogan... It's not easy.
“David Silva didn't play against Tottenham, so they have to fight, be patient work and work because their time is coming.
“I saw today the schedule today and said ‘wow! how many games do we have?’
“Phil is a shy guy, but I would like him to talk to me. He’s 19 and that is normal and and he’s OK and in the right place.
“They are incredible guys and of course, they are not happy when they don’t play, but around the corner there is always a chance and that is when you have to talk.
“Phil, David or Fernandinho understand completely.”