Olivera was stretchered off in Uruguay's clash with Peru, but has reported he's okay.
"I am feeling better, but at first I was really frightened, because it could've been much worse. Thank God it was just a sprain, now I have three weeks to recover," the 24-year-old for Getafe fullback said on Sport890 radio.
“I heard a noise and it hurt so much, I feared the worst, that it was a cruciate ligament tear. I was so anxious waiting for the test results, everything was whizzing around my mind, but the doctor gave me the good news and I was so happy."
He added, “I'll be in Italy from July 4, Walter Gargano and Edinson Cavani told me how much Uruguayans are appreciated at Napoli. Cavani said it's a very demanding place with a lot of pressure, but I will give my best."