The 17-year-old Santos midfielder has been strongly linked with a switch to the Stadio Delli Alpi but Moggi played down such talk.
"As for Diego, there is too much hype about him and we are not interested. After all we already have the best youngster in the world - Ruben Olivera," declared Moggi.
Olivera is a 19-year-old Uruguayan striker and has made several outings for the Juve first XI.
Moggi feels some of the young players today are overhyped and overvalued and pointed out the vast money Roma spent on Italian ace Antonio Cassano.
"Someone like Antonio Cassano is now only worth around a third of the £20 million that Roma paid for him two years ago," added Moggi.
