Madrid, April 20 -- FC Barcelona could be without striker and top-scorer Robert Lewandowski for next weekend's Copa del Rey final and the semifinals of the Champions League, after the club confirmed on Sunday that he has suffered a muscle injury.

Lewandowski was forced to leave Barcelona's thrilling 4-3 win at home to Celta Vigo in the 77th minute, and on Sunday morning the club published a medical report stating, "tests carried out this Sunday have confirmed that first-team player Robert Lewandowski has an injury to the semitendinosus muscle in his left thigh."

The club did not give a possible return date, only stating: "return to team training will depend on how the injury progresses." However, it seems virtually impossible that he will...