Juve GM Beppe Marotta says the club is prepared to go into the new season with both Brazilians, but will consider offers for the pair for the remainder of the summer market.
He said: "Diego and Melo occupy an important place in the project, but if an important offer came it would be evaluated.
"This applies not only to them. In football today there are very few who are non-transferable.
"To reinforce adequately, we must make sacrifices with our playing staff, no club can afford to ignore serious offers."