FC Barcelona will be without Spanish international midfielder Gerard López for up to two months.
A first round of tests on the 23-year-old's left knee revealed an injury to his cruciate ligament and also a cartilage problem, which could mean another lengthy absence for a player sidelined for long spells over the last two seasons.
Gerard's latest setback came in only his second league start of the campaign. He had just returned to the side in an unaccustomed defensive role for the game a week ago against RC Recreativo de Huelva, but lasted a mere 13 minutes of the match on Sunday after coming off worse in a challenge with home forward Julio Dely Valdés.
He could now miss Barcelona's four remaining second group stage encounters in the UEFA Champions League, starting with the Group A tie against Internazionale FC at Camp Nou on 18 February. The injury is a further blow to Gerard, who was a Champions League finalist with Valencia CF in 2000, prior to his €20m transfer to Barcelona that summer.