Dortmund are currently two points clear of Bayern Munich after 27 matches.
ℹ️ @AchrafHakimi hat sich im Spiel #BVBWOB den Mittelfuß gebrochen - Saisonaus. 😫 Er wird in Madrid operiert.— Borussia Dortmund (@BVB) April 1, 2019
Auch Abdou #Diallo fällt zunächst aufgrund muskulärer Probleme aus. Wie lange ist noch unklar.
Gute Besserung, Jungs! 💪 pic.twitter.com/MYtgOpC4bh
Champions League winner Hakimi is coming to the end of the first season of his two-year loan deal from the Spanish heavyweights, and has played 21 times in the league, scoring twice and providing four assists.
The 20-year-old appeared set for his Africa Cup of Nations debut with Morocco in three months, but his participation in the continental showpiece - scheduled to start in Egypt in June - is now in serious doubt.
Despite predominantly featuring on the right side of Dortmund's defence this season, Hakimi has mainly been used on the right side of the Atlas Lions' defence by Herve Renard, with Noussair Mazraoui or Nabil Dirar used on the right.
Hakimi's absence could (re)open the door for Schalke 04 left-back Hamza Mendy, who's made just seven Bundesliga starts so far this term.