Speaking to United Review, Pogba admitted that he had talked with Greenwood about his potential - and what he wants to see from the teenager.
"Everybody knows about his talent but we've seen talented players here doing great at the start and then end up at other teams," Pogba said.
"We don't want that. We want to protect him and how to protect him is, for me, just to say that he didn't do anything yet.
"He knows it - I like to speak with him.
“I want to see him, with his quality and his talent, score above 15 goals a season and with the time we have left [this season], easy. He knows he has to work hard and that he's not there yet."