Marshall told the Sunday Mercury: "Kasper is a great kid, he's a young lad who is very similar to his father in terms of the way he plays in goal, he's not got the stature of his father but he is a phenomenal talent.
"There's no bitterness from my point of view, if I'm playing and the manager decides to change things around then I have to look at myself.
"Kasper's a really nice kid and I've got a lot of time for him.
"Sometimes players can come in and keep themselves to themselves but Kasper has made himself centre of attention.
"He's confident, boisterous and a great lad. There's aspects of his game that he needs to improve but as long as he takes that on board he will have a bright future.
"There's no doubt that he has got a long career in football."