After joining from Leeds last summer, Phillips, who underwent shoulder surgery in September, only made four substitute appearances for City prior to the World Cup.
Following the tournament in Qatar, the 27-year-old was then described by Guardiola as having returned overweight and not in condition to do training sessions or play.
He has subsequently come off the bench twice against Chelsea as City beat them 1-0 away in the Premier League last Thursday and then 4-0 at home in the FA Cup on Sunday.
And with City set to face Southampton away in the Carabao Cup quarter-finals on Wednesday, Guardiola said on the possibility of Phillips making a start: "He's always ready. Of course I think (it takes) a little bit of time for some aspects but he's ready and we are delighted about that."
Guardiola added: "I think he's an intelligent player - normally holding midfielders are so clever and intelligent - and has an incredible work ethic in the training sessions.
"He was educated at Leeds with Marcelo Bielsa, with Jesse Marsch (as well) but especially Marcelo, the fact of the commitment every training session, every game. So I don't have doubts about that - but of course there are patterns and movements, things that need time and games and games.
"He arrived this season and unfortunately was injured which meant he could not be there, but that's why step by step he will get it."
Jack Grealish, who joined City from Aston Villa in the summer of 2021, last week spoke of how difficult it had been to adapt to playing at the club.
When that was put to Guardiola, in relation to Phillips and new players adapting at City, he said: "For me it's not hard - the way we want to play is so simple. Run without the ball, everyone, to help each other, and with the ball, be in the positions to get the ball in better conditions.
"I read the words from Jack and I understand - at Villa they said, 'Do whatever you want, move here, move there, right, left'. Here, it is completely different, you stay more in position and the ball comes where you want, and sometimes you have a little bit more time for that.
"We spoke a few times with Jack about positions, about tactics, and he understands completely. He's so comfortable with that. But honestly it's not difficult."
Guardiola has won the League Cup four times, making him the joint record-holder alongside Brian Clough, Sir Alex Ferguson and Jose Mourinho.
He was keen to stress that it would not mean anything to him to become the manager with the most successes, and said: "I don't know if the reason why you are the best is for the trophies you won.
"(And) I said many times, we won a lot in a short period of time, but in my case, I was at three fantastic clubs (Barcelona, Bayern Munich and City), and I never forget the success belongs to the players, the structure, the hierarchy, the foundations of the organisation."