The Norwich winger is attracting interest from Sunderland and Reading and Cassell told City's website: "Yes, he's another of our boys playing in the Championship and is a creative player who works hard. Crofty is a top class individual and you just enjoy seeing people of his type that have never been a problem getting the benefits of success.
"He, more than anyone, really deserves it and he keeps working and working. You knock him down and he keeps getting up and that's the mental strength you have to have as a winger, to keep getting the ball and taking people on, and Crofty's shown he can do that.
"It's going to be a very interesting future because some of these boys are only 22 and 23, so you put two or three years experience on there and it wouldn't surprise me to see some of these players coming back into the Premier League because they are mature and we know they've got ability."