Barcelona midfielder Andres Iniesta has been ruled out for up to three weeks with a hamstring tear, the European and Spanish champions said on Thursday.
Iniesta had to be substituted in the first half of their King's Cup quarter-final triumph over Real Madrid on Wednesday, which set up a semi-final clash with Valencia or Levante next week.
The scorer of Spain's winner in the 2010 World Cup final will be cutting it fine to be fit for Barca's return to Champions League action in the first knockout round at home to Bayer Leverkusen on February 14.
Iniesta joined a growing list of absentees for Barca coach Pep Guardiola who lost Chile forward Alexis Sanchez to a shoulder injury for two weeks in the same game.
David Villa, Ibrahim Afellay and Andreu Fontas are all injured, Seydou Keita is competing with Mali at the Africa Cup of Nations and Brazilian full-back Maxwell was sold to Paris Saint-Germain this month.