Although the German side's sporting director, Michael Zorc, insisted no deal has been struck, speculation increased on Thursday when coach Peter Bosz revealed Dembele missed training and that the club could not contact him.
Although Dortmund would ideally like to keep Dembele, the player will want to move to Barcelona, and they will still receive over £100 million for the 20-year-old.
Callum Bunce of Ladbrokes said: "Dembele couldn't have made his intentions any clearer with his recent actions, and the money suggests it's surely only a matter of time before the club let go of their prized asset".
Borussia Dortmund attacker Ousmane Dembele has captured the interest of Spanish rivals Real Madrid and Barcelona this summer.
Instagram photos can indicate whether someone is depressed
Ideally, Danforth says the best outcome of technology like this is getting those individuals the medical support that they need. The team found that people with depression did indeed post photos that were, on average, bluer, darker, and grayer.
Dortmund also say that it is "not now likely" that they will let Dembele depart.
The statement added: "During this meeting, representatives of FC Barcelona submitted a bid which did not correspond to the player's extraordinary footballing and additional value of the player and the present economic situation of the European transfer market". I have no idea why he wasn't there. Aarons cited a report from French publication L'Equipe, as well as one from Sky Germany, both indicating Dembele will move to the Camp Nou, with L'Equipesaying the ex-Rennes ace will fly to Barca imminently. "We've tried to reach him and we hope nothing bad has happened".
Ahead of Dortmund's DFB Pokal first round match against Rielasingen on Saturday, Bosz told reporters at a news conference: "It's true, he wasn't there today and to be honest I don't know why".