Guardiola again overlooked Kalvin Phillips when selecting his side at Villa Park, fuelling further speculation the England midfielder could leave the club in January.
Phillips has failed to establish himself at the Etihad Stadium since his move from Leeds in 2022. Guardiola said: "I don't know what will happen. I feel so sorry for my decisions for him.
"He doesn't deserve for one second not to have minutes but it's just that I visualise things and struggle a little to see him."
Kevin De Bruyne, who has been out since undergoing hamstring surgery in August, has been named in City's squad for the Club World Cup later this month but it is not yet clear if he will be fit to play. Guardiola said: "Maybe it is a little bit early, but I don't know."