Ferreira has been working with the loan players at Chelsea and admits James is one who has impressed him.
"He is a top player and a fantastic guy. For me it was a pleasure working with him last season when he was at Wigan. You could see the player's potential and I thought he could come back to the club and do well," he told Goal.
"But if you ask me if I thought he would do what he did, I wouldn't have believed you! But I'm glad he surprised me. He is a fantastic guy, he is easy to work with and what he has done this season has been fantastic.
"He is very good offensively, with fantastic crossballs. You could see it in Wigan. But he has also improved defensively. He is still a young player and is learning."