Dembele missed first-team training on Thursday and Bosz revealed the France global had not answered his phone when contacted by the club.
"There has been a discussion with the Catalonian Football Club FC Barcelona in regards to a possible transfer of Ousmane Dembélé to FC Barcelona", read the statement.
With Dortmund's new coach Peter Bosz placing an emphasis on youth development, it will be no surprise to see him give Mor the chance to play week in week out.
"Dembele didn't show up for training today", Bosz said. Because of that behaviour we will sanction him.More news: The Guy Who Wrote the 'Google Memo' Just Might Sue
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"He wasn't there this morning and if I am completely honest I have to say that I have no idea why he wasn't", said Bosz. The club also insisted that the player was now in Dortmund, contrary to other rumours.
"We have also suspended the player until after the cup game at the weekend".
Dortmund only signed Dembele from Rennes last summer for €15m and the Frenchman has impressed in his debut season in the Bundesliga.
"I talked to Dembele yesterday. We hope nothing awful has happened".