German champions Bayern Munich will have to open their Bundesliga season without star man Arjen Robben due to injury. Bayern's official site quoted doctor Hans-Wilhelm Mueller-Wohlfahrt as saying that the Holland winger has been diagnosed with a thigh tear that could keep on the sidelines for two months. "This diagnosis is naturally a shock," said Robben. Robben, who helped his country reach the World Cup final this summer, inspired Bayern's double triumph last season.