The Manchester City midfielder has returned home and is currently observing 10 days of self-isolation.
Grealish returned from November’s international break early after picking up an injury head of England’s game against San Marino, and Foden reported back to the City Football Academy with a leg problem.
“Jack is getting better after he went to the national team,” Guardiola revealed at his pre-match press conference.
“Phil Foden came back with a knock and a problem with his leg, but he is getting better and, unfortunately, Kevin got positive from COVID in Belgium and will be isolating for 10 days.
“Jack, I don’t think [will be available]. Phil, we will see.”
The playmaker has been vaccinated and the manager says his only concern is that the 30-year-old recovers well, rather than the impact his absence will have on the team.
“Forget about the fitness, forget about the momentum,” he added.
“He is positive. He has to recover well and try and be healthy. The human being is more important than anything else.
“When one person is positive we have to be careful because people are still dying. He was vaccinated, so now he is more protected. Hopefully the symptoms will be minor.
“When he comes back negative, he will start again to train with us as soon as possible.
“We are not concerned about the rhythm or what we are going to miss. The person is more important.
“When someone gets a positive you have to be careful. We have to help him and hopefully it goes well whilst he is isolated.”