The 40-year-old is aware of his former player's remarks over the way he left the Spanish club and has offered his version of events prior to the summer exit
The 21-year-old insisted he would not return to Barca if he was called with an offer from the coach because Guardiola never gave him a chance to shine in last season's Champions League final against Manchester United.
Bojan left the Spanish and European champions two months after their famous 3-1 win at Wembley and joined the Serie A club for an initial €12 million [£10.5m] following the tension with Guardiola.
The coach appeared sympathetic with the Roma forward and has taken note of the frustration still felt by his former starlet.
"He [Bojan] did everything to help us. I have good memories of him and I understand his disappointment as I used to play football too," Guardiola told the press.
"He is still young and in two years he will be back here. He now has time to show that he can return to this club.
"I would have liked to have helped him more, but I couldn't. I have to ask whether we did something wrong.
"If I am still the coach should he return, then I will need convincing he can be a Barcelona player. He is young and has a great future, but the success depends on him."
The coach then went on to talk about their Liga clash at home to Racing Santander on Saturday.
"Racing have had 15 days to prepare for this game, we have only had four players [because of the international break]," added Guardiola.
"They are a good team and their coach [Hector Cuper] is a maestro, but we must try to play a fresh and sparkling game so we can beat a team who defend very well."