De Bruyne has been absent for the past three games after having tested positive for COVID-19 at the end of the November international break.
Grealish meanwhile has been injured since the international break, while Foden was forced to miss the wins over Paris Saint-Germain and West Ham.
Speaking at Tuesday’s pre-match press conference ahead of the trip to Villa Park, the City boss provided the latest news on all three.
“Kevin still hasn’t trained. He was negative for the last COVID Test but could not train,” the City manager revealed.
“We have few players, Kevin will be back but he needs time to be fit. All the people with COVID explain the drain and tiredness and they need time.
“Kevin needs to be fit to show his top quality.
“Jack, yesterday was the first minutes training with the team and Phil Foden too.
“Both will be tested tomorrow to see if they can travel to Birmingham.
“Phil and Jack are still in the same position, the same situation.
“Maybe they can play tomorrow, but maybe not a lot of minutes. The doctor will see tomorrow.
“We are in a difficult position because a lot of players have played a lot of minutes.
“We will see what happens tomorrow after today’s training. Both will be tested tomorrow to see if they can travel tomorrow to Birmingham.”
“Yeah. John is good, yeah,” the boss added.
“We are a few people. Aymer is out. We have to come back.
“We never complain when the players can’t play because of injury or red cards, for any reason.
“I trust a lot all of the squad and when one can’t play, another comes in.”