Barcelona defender Aleix Vidal has been ruled out for five months following ankle surgery.
Vidal, 27, dislocated his right ankle after clashing with Theo Hernandez in the 85th minute of the Catalan club's 6-0 win against Deportivo Alaves on 11 February.
Barcelona confirmed in a statement that the Spain international was operated upon in a hospital in Vitoria and that he will miss the rest of the season.
Manager Luis Enrique said he was "upset" about Vidal after the game at Mendizorrotza.
"We really regret the injury to Aleix Vidal. We hope it's not too serious," he told the club's official website.
Vidal has made six La Liga appearances for Barcelona this season, scoring two goals. He joined the club from Sevilla in June 2015 for an initial fee of £13m ($16m).
Barcelona midfielder Ivan Rakitic said after the Alaves match that he hoped Vidal's injury was not too serious.
"The match went well but we hope Aleix hasn't suffered too serious an injury," he told the club's website.
"I hope it doesn't turn out to be as bad as it looks, I was quite shocked. Hopefully he'll be back soon as he is a great guy and he was playing excellently."
Enrique told Sport: "I'm devastated about Aleix's injury, how it happened and what it means for him and the team.
"To see a serious injury for a teammate is unpleasant for everyone. We have to think about lifting his mood. Hopefully he's back as soon as possible. He's in the best hands."
Alaves left-back Hernandez apologised to Vidal and said there was no ill intent behind his challenge.
"I am very sorry, I have gone for the ball. I am very sorry that Aleix has a serious injury," he was quoted as saying by Sky Sports.
Luis Suarez, Lionel Messi, Ivan Rakitic and Neymar all scored at Mendizorrotza as Barcelona extended their unbeaten run in La Liga to 15 matches.
The Catalan club are a point behind leaders Real Madrid, who beat Osasuna 3-1 at El Sadar on 11 February.