Ousmane Dembele found himself fined and suspended by the Bundesliga side earlier this week when he failed to show up for training.
A number of reports have claimed that the 20-year-old’s actions were a move to help force through a transfer to Barcelona, who are rumoured to be interested in his services.
The decision to extend the suspension was taken after a meeting on Saturday night between manager Peter Bosz, chief executive Hans-Joachim Watzke and sporting director Michael Zorc.
“Our focus now is on a concentrated preparation of the team for the Bundesliga opening match against Wolfsburg in the coming weekend,” Zorc told Dortmund’s website.
“Ousmane Dembele has the possibility to do individual training off the group.”
Dembele joined Dortmund a little over 12 months ago from Rennes on a five-year contract and scored 10 times in 49 appearances in all competitions last season.