The 34-year-old, who went off on a stretcher after hurting himself while catching a cross and clearing the ball, was replaced by Willy Caballero.
"Of course he has an injury, probably [out] for some weeks," said Guardiola,
"I don't know if he will be available again this season."
The 0-0 draw - in which Bravo came off after 79 minutes - was only his sixth clean sheet in 22 Premier League games since his £15.4m summer move from Barcelona.
Manchester City boss Pep Guardiola does not know if Claudio Bravo will play again this season after the keeper was injured during Thursday's Premier draw with cross-city rivals United.