Guardiola hopes to have the Brazilian striker in two to three months but accepts he could be without him for the rest of the campaign.
"I don't know if Gabriel Jesus will play again this season. They say [he could be out for] two or three months," Guardiola said. "Last night he had an operation, it was good, really good.
"The most important thing now is a good recovery and he is going back when he will be fit, I don't know if it will be the end of the season or next season.
"Now to be calm, all our support to him and his family and waiting for when he is coming back."