As the Brazil superstar's world-record switch to Paris Saint-Germain progressed on Wednesday, with Barcelona excusing him from training after Neymar told them of his intention to leave, Dembele was identified in reports as a player of interest to the Catalan giants.
The €222 million move ran into interference from La Liga on Thursday and Bosz told a news conference ahead of Dortmund's DFL-Supercup meeting with Bayern Munich this weekend that it would be unwise for the Bundesliga club to be drawn into the hypotheticals of a fully blown transfer saga.
"We are not worrying about Dembele going to Barcelona," said the former Ajax boss, who was similarly unmoved by the prospect of spiralling global transfer costs.
"If I had to worry about what could happen, I would not sleep well."
One player who once threatened to operate in that stratosphere was Dortmund playmaker Mario Gotze, but the 25-year-old is being carefully managed having returned to action in pre-season following the metabolic disturbances that left him sidelined for five months.
"It is clear that Mario needs time to play, but we have to be careful too," said Bosz, who will be without Andre Schurrle, Emre Mor and Erik Durm for the showdown with the Bundesliga champions at Signal Iduna Park.
"So far, if he has played, we'll take him back a little [to recover]. He needs rhythm and is in a very good way."