Dembele is being targeted as a replacement for Neymar, who left Barcelona for Paris Saint-Germain last week in a record-shattering $A331 million deal.
And the 20-year-old was absent from training without permission on Friday (AEST), with Dortmund head coach Peter Bosz confirming the club had been unable to contact Dembele.
Speculation that a move to Barcelona was imminent soon mounted before BVB issued a statement saying a bid had been lodged by the Catalan giant but it did not meet its valuation for a player it signed from Rennes for $22.4 million last year.
Dortmund has now announced Dembele will be punished for his no-show and will be banned until after this Sunday's (AEST) DFB-Pokal clash with Rielasingen-Arlen.
Sporting director Michael Zorc said: "Ousmane Dembele was missing from BVB training today without permission and apparently decided voluntarily to do that.
"Of course, such misbehaviour will be sanctioned.
"On top of that, after consulting our coach, we have decided to ban the player from training and matches until after the cup match this weekend."