Dembele is being targeted as a replacement for Neymar, who left Barcelona for Paris Saint-Germain last week in a record-shattering €222 million (A$331.91 million) deal.
And the 20-year-old was absent from training without permission on Thursday, with Dortmund head coach Peter Bosz telling a news conference 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 giants but it did not meet their valuation for a player they signed from Rennes for €15 million (A$22.43 million) last year.
Dortmund have now announced Dembele will be punished for his no-show and will be banned until after this weekend's DFB-Pokal clash with Rielasingen-Arlen.
Sporting director Michael Zorc explained: "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."
Earlier, Dortmund had released a statement which read: "Borussia Dortmund has held talks with the Catalan football club FC Barcelona regarding the possible transfer of the BVB player Ousmane Dembele to FC Barcelona.
"During this meeting, the representatives of FC Barcelona submitted a bid which did not match the player's extraordinary footballing ability or value to the club, nor the present economic market situation of the European transfer market. BVB therefore rejected this offer.
"As there is no other offer from FC Barcelona to date, there is currently no transfer of the player to FC Barcelona and this is not currently likely."
Dembele scored 10 goals and supplied 21 assists in 49 games for Dortmund in his debut season with the club.