But Emery says: "I believe in Jhon Duran,. When we signed him, his process is being how we can make a plan. He is 20 years old and he was 19 years old when he arrived here. He's progressively getting better. He's adapting. Even this year.
"He started with an injury. He started playing in August or September, he didn't have a pre-season. He was getting better and now he is in his best moment now. His adaptation wasn't easy. Last year or this year.
"Now I think he's showing his capacity as well, particularly in the last match (Liverpool). He's here because we wanted him and we want to keep him as well. We are thinking he can improve us, stay here and grow up with us. But, of course, always we have to be ready in case there's something we have to do in the transfer window with every player - even him - but at the moment, I'm happy with him."
Emery added: "I speak to him a lot, individually and collectively about him, even with his agent because his agent helps with him as well. His potential is great, but he needs a plan and I am trying to do it.
"His numbers are more or less good, scoring some goals, some penalties as well through him we got. If we can analyse the minutes he played when he was competitive, I think he was helping us."