The 37-year-old Polish international will miss the highly anticipated El Clasico against Real Madrid on October 26.
Lewandowski sustained the hamstring injury during international duty with Poland in a World Cup qualifier against Lithuania, in which he played the full 90 minutes and found the back of the net.
However, subsequent assessments revealed a tear in the biceps femoris of his left leg - a setback that now sidelines him for several key fixtures across both domestic and European competitions.
The timing of the injury couldn't be worse for manager Hansi Flick, who must now prepare for one of the season's most decisive fixtures without his first-choice striker. Lewandowski is expected to miss LaLiga clashes against Girona, Elche, and Celta Vigo, in addition to Champions League group matches versus Olympiacos and Club Brugge.
While Barcelona's statement was vague, only noting that the striker's return "will depend on how the injury evolves," Spanish media reports estimate a recovery period of four to six weeks.
Lewandowski's absence adds to an already congested treatment room at Camp Nou. Fellow attackers Dani Olmo and Gavi are also unavailable, with Olmo nursing a calf strain and Gavi facing a longer-term layoff. Goalkeepers Marc-Andre ter Stegen and Joan García are also sidelined, with the former recovering from back surgery.
However, there are some silver linings. Promising youngsters Lamine Yamal and Fermín Lopez have returned to full training, and Brazilian winger Raphinha is pushing to be match-fit in time for El Clasico after missing the last three matches due to a thigh problem.
Juventus have reportedly made official enquiries to Real Madrid over a potential loan move for midfielder Eduardo Camavinga as they step up plans for a midfield rebuild under manager Luciano Spalletti.
Barcelona have completed the signing of Anthony Gordon from Newcastle United in a deal worth around 69.3 million pounds, bringing the England forward to the Catalan club on a contract running until 2031.
Barcelona's aggressive start to the transfer window is continuing, with Bernardo Silva now emerging as another major target for the Catalan giants.
Barcelona captain Ronald Araujo has admitted he reached a breaking point during the season after struggling with his mental health, saying he realised he needed help following his sending-off against Chelsea in the Champions League.
