Mohamed Zidan will be sidelined for six months after his injury was diagnosed to be a ruptured cruciate knee ligament.
The Egypt forward’s father, Abdullah Zidan, Zidan’s Fathersaid that he will undergo surgery in a couple of days.
Zidan was stretchered off the field during Borussia Dortmund’s 1-1 draw with Hoffenheim in the Bundesliga on Sunday.
His knee twisted as he fell down unchallenged after just 27 minutes before some 90.000 fans.
The injury is a big blow for Dortmund, who seek qualification to the Champions League next season.
They are one point adrift of third-placed Werder Bremen with three games to go.
Zidan scored six goals in the Bundesliga this season.