Phillips has only played 58 minutes for City in an injury-hit spell since joining from Leeds and was omitted from the squad for the Carabao Cup win over Liverpool because Guardiola said he returned from the World Cup overweight.
But Guardiola feels Rodri, his first-choice holding midfielder, needs a break at some stage and will put Phillips in his side either against Chelsea on Sunday or Southampton on Wednesday.
The City manager said: “For sure he will play in the Carabao Cup. Sunday, we will see. I had the feeling that last week he is back. A good feeling. He worked to change my mind so that he can play.
“It will maybe be a good lesson for him in the future. A football player has to be perfect for 12 months because you can enjoy and do whatever you want but you have to be ready because this level is so demanding and to play every three days you have to be fit and if you are not fit, nothing. In the last week, he has improved his level.”
Phillips, who made two substitute appearances at the World Cup, was also out for two months towards the end of the last campaign and Guardiola added: “Kalvin at Leeds was injured for a long part of the season. He came and then he could not train and needed an operation on his shoulder. He fought to go to the World Cup and that’s why he was not playing for a long period. In the middle you need rhythm and concepts and he has not been here for five or six years but Rodri cannot play every game. Look at what happened against Chelsea, he had cramp after playing all the minutes and needs rest.”
Both Chelsea and Leeds supporters have sung songs about Phillips’ weight, which the England international had taken in good spirits and Guardiola added: “He has a big sense of humour. It was funny from the Chelsea fans.”