Barcelona midfielder Marc Bernal (17) will miss most of the season after he ruptured his anterior cruciate ligament (ACL), the LaLiga club said on Wednesday.
Bernal sustained the injury to his left knee during Tuesday's 2-1 victory at Rayo Vallecano, where he was forced off the pitch in the final minutes.
Bernal, who made his debut in Barca's opening-day win over Valencia, also suffered an associated injury to the external meniscus. "He will undergo surgical treatment in the coming days," Barcelona said in a statement.
Barcelona face Real Valladolid next in LaLiga on Saturday.