Dortmund s Norwegian forward Erling Braut Haaland. AFP
"It is too early to name an exact date" when Haaland will return, "but we hope he can play again this year," sports director Michael Zorc said Saturday.
"It will take a few more weeks."
The 21-year-old is currently recuperating with his family in Norway.
Having scored 70 goals in 69 games since joining Dortmund in January 2020, the loss of Haaland is a blow to the Bundesliga club who started the weekend second in Germany's top flight.
Dortmund hope he will be back before their Bundesliga showdown against current leaders Bayern Munich on December 4.
"At the moment, it's a matter of him clearing his head a bit, as he can't do much yet," added Zorc.
Haaland has not played since Dortmund's 4-0 thrashing at Ajax in the Champions League a fortnight ago.
His absence will also be felt by the Norwegian team, with Haaland to miss two crucial World Cup qualifiers against Latvia and the Netherlands on November 13 and 16.
Norway have not participated in a major tournament since Euro 2000 but currently sit second in Group G, two points behind the Dutch and two ahead of Turkey.
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