Dinamo Zagreb forward Olmo has been linked with a move to City, while Roma and Milan have also been credited with an interest in his services.
Barcelona are thought to be keen on bringing Olmo back to the club, having signed him to their famed academy as a nine-year-old in 2007.
His time in the Barca youth set-up overlapped with Guardiola's glittering spell in charge of the Blaugrana, Spain international Olmo leaving for Dinamo in 2014.
Olmo was on target as he gave Dinamo the lead with a rasping close-range volley against City on Wednesday, only for the Premier League side to cruise to a 4-1 win, ending the Croatian club's hopes of progression from Champions League Group C.
Guardiola was asked in his post-match media conference if Olmo can be an expensive player in Europe, to which he replied: "He's a top player - he has a bright future, of course.
"His performance today shows it. About the transfer and the money he deserves, that is not the point. The point is he is an incredible player and I am pretty sure he is able to play in the strong leagues in Europe. Hopefully if Dinamo wants and he wants, it can happen."
City have now scored 500 goals under his stewardship, with Guardiola adding of that milestone: "It's nice - 500 times of joy. You know, when we score a goal, it's the best moment of this game, so we enjoy a lot.
"These four years together, overall we have had an incredible amount of fun moments, so it was nice. Hopefully we can score 500 more... in two months!"