Batshuayi was hurt in injury time on Sunday, left the stadium in Gelsenkirchen on crutches, and was taken to hospital for treatment.
Dortmund says on Twitter he ”will probably be out for the rest of the season (but) an appearance for the Belgian national team at the World Cup in Russia is in the realm of possibility. Get well soon, Michy!”
Batshuayi also took to social media, tweeting his season ”is probably over, and I wont be able to pay (at)BVB back for their confidence … Thank you all the amazing amount of love I received since yesterday. Wishing my teammates the best for the final days. See you soon.”
Batshuayi, who is on loan at Dortmund from Chelsea, was injured in a sprint for the ball when he collided with Schalke defender Benjamin Stambouli.
His absence will hit Dortmund hard at the sharp end of the Bundesliga. He scored seven goals and set up another in 10 league appearances since his winter switch as a replacement for the Arsenal-bound Pierre-Emerick Aubameyang.
Dortmund is fourth in the last Champions League qualification place with four rounds remaining. The side faces tough games against Bayer Leverkusen at home, Werder Bremen away, and Mainz at home before its last game at Hoffenheim.