Martino is delighted working with the former Club America prospect.
He said, "We understand that Diego is the future of the national team, we do not want to neglect that point. He seems to us a player who is extremely important and who can be much more important.
"When we call him, we think of him so that, in one way or another, he can participate and play. We always want to have him, train him, see in what way we can contribute and help him grow."
On talk of Lainez rejecting an offer from MLS, Martino was coy.
He continued: "These issues are absolutely personal. Obviously, if at any time you need the opinion of any of us in the coaching staff, we will try to give it to him, but I don't like to do it without asking for it because we get into personal and family terrain."