He admitted Gray hasn’t played center-half before but believes his talent and attitude allow him to adapt quickly.
Postecoglou is confident that wherever Gray plays, he will excel because of his hunger to improve and his composure on the pitch.
He told reporters: “Who knows. But you can't lose sight of the fact he's never played there before. I just think he's a fantastic player. I'm so pleased he's at this football club. And he's a fantastic kid as well. He just wants to learn, no task is too much for him, he tackles everything with a real kind of calmness, that belies his years. He wants to learn, he wants to get better. We are just very, very fortunate to have him at our football club. Whatever position he ends up playing, he's going to be outstanding. He has that attitude of wanting to improve, wanting to get better. He's already set a high benchmark. There aren't many 18-year-olds who you could throw into the Premier League, play out of position in such an important area of the park, and handle it the way he has. Just brilliant.”