Alexis Sanchez will miss Barcelona's Champions League game against Bayer Leverkusen on Wednesday after injuring his leg in his team's 3-1 win over Sporting Gijon.
Alexis went on as a second-half substitute on Saturday and helped Barcelona secure the victory before tearing a muscle in his right leg that will sideline him for 10-15 days.
"He is a vital player and we have lost him... another difficulty to overcome," said Barcelona coach Pep Guardiola, who was already without injured striker David Villa.
"He is 22 years old. He has to grow and learn how to play every three days."
The forward played for Chile in a friendly against Ghana in Philadelphia on Wednesday and had time for only one training with Barcelona before the Spanish league game.
Alexis missed various games at the beginning of the season with a muscle injury.