By FOX Sports Staff
Mkhitaryan completed his €27.5 million move to Dortmund a fortnight ago and made his debut in a friendly match against Basel, where he set up Marco Reus' goal in the 3-1 win.
However, Dortmund have revealed that Mkhitaryan has suffered an ankle injury and is set to be out for a month.
"Borussia Dortmund have to make do without Henrikh Mkhitaryan in the coming weeks," a club statement read.
"According to team doctor Markus Braun he will probably be unavailable for up to four weeks."
Dortmund begin their new campaign on 10 August against Augsburg.