Dutch newspaper De Telegraaf published pictures on Wednesday of Gundogan's agent meeting with Manchester City technical director Txiki Begiristain in an Amsterdam Hotel.
"I do not understand the excitement about all of this. We are also looking forward to next season. We are planning and we speak to advisers and players - it is part of the everyday job we do," Tuchel said when asked about the meeting in a press conference.
"Am I convinced that [Gundogan] will stay? I don't really know.
"I can only say that once he has actually signed. I know what we can offer him and if that's enough for him to stay then so be it."