Peruvian forward Paolo Guerrero could miss the FIFA Club World Cup Japan 2012 with Corinthians after suffering a knee ligament strain last weekend.
The 28-year-old striker was replaced in Sunday's 3-1 defeat to Sao Paulo after 40 minutes of play.
Guerrero scored the only goal for O Timao in the 13th minute but had to leave the pitch just before the break due to an injury to his right knee.
A first examination on Monday made it clear that Guerrero sustained a moderate strain of the medial collateral ligament of his right knee and will be unavailable for no less than 15 days.
The FIFA Club World Cup will begin December 6 with the final to be played at Yokohama's International Stadium Dec 16. Corinthians will play their first match in the Club World Cup on Dec 12.
The tournament, contested annually by the champions of each of the continental confederations, will also feature European champions Chelsea (England), Ulsan Hyundai (South Korea), Al Ahly (Egypt), Monterrey (Mexico), Auckland City (New Zealand) and Sanfrecce Hiroshima (Japan).
The Peru international hitman joined Brazilian giants Corinthians earlier this year from German side Hamburg, having started his senior career with Bayern Munich.
In a recent interview, Guerrero said he expects Corinthians to come face to face with Chelsea in the final of the FIFA Club World Cup.
"We expect a duel against Chelsea", he told Brazilian daily Lance. "But first we must concentrate on our work.
Corinthians squad for FIFA Club World Cup:
Goalkeepers: Cassio, Julio Cesar, Danilo Fernandes.
Defenders: Alessandro, Fabio Santos, Guilherme Andrade, Chicao, Paulo Andre, Wallace, Anderson Polga, Felipe.
Midfielders: Ralf, Paulinho, Guilherme, Edenilson, Danilo, Douglas, Giovanni.
Strikers: Emerson, Guerrero, Jorge Henrique, Romarinho, Martinez.
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