Reja insists the 23-year-old is still a key part in his plans for the future at Lazio.
He said: “Zarate will not be leaving Rome and I can confirm this 200%.
“I read an article in the Gazzetta dello Sport yesterday linking the boy to Juventus but I can declare that there is no truth to the story.
“I simply don’t know where such an idea sprung from.”
