Morocco's Marseille forward Amine Harit (25) has sustained a knee injury, the Ligue 1 club said on Monday, just over a week before the country's World Cup opener with Croatia.
"Harit, injured during the match against Monaco on Sunday, has suffered a sprain of the cruciate ligaments of the left knee," Marseille said in a statement.
The club did not give a timeline for his recovery after he was carried off on a stretcher before the hour mark during Marseille's 3-2 win at Monaco.
French media said he was likely to miss the World Cup.
Morocco's team delegation, including seven players, landed in Doha, Qatar on Sunday. The rest of the squad are due to join them once they are discharged by their respective clubs.
Morocco kick off their World Cup campaign on November 23 against Croatia and also face Belgium and Canada in Group F.