Former Holte End hero Saunders coached the midfielder at Newcastle United when Graeme Souness was in charge and witnessed his unprecedented work rate and determination first hand.
"I've got nothing but admiration for James and I'm really pleased how his career has progressed," he told Villa's website.
"I use him as an example to our players now. I've not worked with a player who works as hard as James.
"As soon as training finished, he would tap me on the shoulder every day and he would keep me out there for hours and I used to enjoy working with him - practising his left foot, his right foot and his free-kicks.
"Darren Ambrose was the other one that stayed out and the two of them stayed behind for hours after training.
"It just shows what has happened to him - through sheer effort and determination he has made himself a player. Obviously he is talented as well but his effort and determination and drive have got him to where he is now."