"I'm devastated," said the 27-year-old Brazilian who tore the cruciate ligament in his left knee during a training match on Saturday.
Edu
"I heard a strange sound and felt a very odd pain and felt dizzy when it happened. I knew it was something serious.
"It is difficult to cope with because I had worked so hard in the pre-season and I was really looking forward to starting a new stage in my career with Valencia and now this changes everything."
Valencia attempt to overturn a 1-0 deficit when they play Hamburg SV in the return leg of an Intertoto Cup final at the Mestalla on Tuesday.