Valencia striker Rodrigo has been ruled out until 2016 with a left knee injury, the Spanish club announced.
The Brazilian player was hurt during Valencia's 2-1 defeat at Atletico Madrid on Sunday and tests done have revealed a partial knee ligament tear.
A statement from Valencia read: "Tests done on Monday revealed that Rodrigo is suffering from a partial tear of his posterior cruciate ligament of his left knee.
"The estimated time of recovery is three months."
The 24-year-old joined Valencia on a permanent basis from Benfica this summer after spending last season on loan at the Mestalla stadium.
Valencia are ninth in the La Liga standings with three wins from their opening nine games.
Los Che are also competing in the Champions League and are second in Group H, three points adrift of leaders Zenit.
Valencia, coached by Nuno Espirito Santo, host Levante in Saturday's city derby.