Super Eagles forward Umar Sadiq has been diagnosed with a rupture of the anterior cruciate ligament (ACL) in his right knee.
The Real Sociedad player suffered the injury against Getafe in La Liga on Sunday.
The Nigeria international moved to La Real just a fortnight ago from Almeria.
He will undergo surgical treatment and could be sidelined for about seven to nine months.
He had joined La Real for a club record €20m up front plus €5m in bonuses to replace Swedish forward Alexander Isak.
His absence could also scuttle Super Eagles coach Jose Peseiro’s plans for the September 27 friendly match against Algeria in Oran, especially given Napoli striker Victor Osimhen will not be available after sustaining a thigh injury that will keep him out for a number of weeks.
The 25-year-old, who has seven caps and one goal for the Super Eagles, made his European debut in last week’s 1-0 win over Manchester United in the Europa League.