Mexico international Dos Santos broke into Barca's senior squad last season, but the rise of fellow young star Bojan Krkic has limited his appearances in the Catalan giants' starting XI this year.
"There is interest from Manchester City," Zizinho told Mexican newspaper El Universal.
"However, I cannot give more information now as Giovani's agent is the one in charge of all this, it's him who is dealing with negotiations.
"I can't say for sure if Giovani will go to another team. There are still games to play in La Liga and while there are he's only thinking about Barcelona.
"We don't want to get ahead of ourselves, there is interest but first he has to concentrate on Barcelona."