Valencia Brazilian midfielder Edu faces a long stretch on the sidelines after damaging knee ligaments during the 3-0 defeat away to Sevilla in the Primera Liga on Saturday.
Valencia doctors said there was a 90 percent chance the player had torn the anterior cruciate ligament in his right knee.
Edu left the pitch in tears on a stretcher after falling awkwardly in the final minutes of the game and is set to miss Valencias remaining Champions League matches in Group D against Olympiakos and AS Roma.
The former Arsenal player was out for seven months last season after tearing the cruciate ligament in his left knee during training.
Valencia striker David Villa also had to leave the pitch on Saturday with an ankle injury.
Quique Sanchez Floress side has been ravaged by injury this season and are already missing Carlos Marchena, David Albelda, Jaime Gavilan, Asier del Horno and Emiliano Moretti with long-term injuries.