Real Sociedad's Nigeria international forward Umar Sadiq will face a long spell on the sidelines after suffering a cruciate ligament injury.
Sadiq was forced off in the 38th minute of Sunday's 2-1 league defeat at Getafe.
It was his third appearance with Sociedad since joining the Basque outfit in a €20 million move from Almeria on transfer deadline day to replace Alexander Isak who moved to Newcastle United.
Tests done on Monday showed he had torn his right ACL.
The LaLiga club confirmed Sadiq, 25, will undergo surgery in the coming days but did not reveal how long he will be out of action.
However, he could miss the rest of the season.
Sadiq, who was Sociedad's top summer signing, made an immediate impact by scoring on his debut in a 1-1 draw against Atletico Madrid on Sept. 3.
He started for Sociedad in their historic first win over Manchester United at Old Trafford in their Europa League group game on Sept. 8.