Liverpool defender Virgil van Dijk says former teammate Rafa Camacho has much to learn.
The wing-back left Anfield for Sporting CP earlier this month.
Van Dijk said, "He is still young, he has a lot to learn. He had been in Sporting youth and probably feels like returning home. I'm happy I hope he is happy.
"He has quality and he knows what he has to do, because we all know that there are many players who have quality but then they lack the rest."
Van Dijk was also asked about Bruno Fernandes, a target for Manchester United, after their friendly this week.
"Sporting are a good team, play good football and have good players. Bruno Fernandes is one of them, but I have no influence on what can happen," he said.