Kilmarnock boss Derek McInnes accepted the lure of English football after Charlie McArthur left Rugby Park for Newcastle.
The 17-year-old centre-back, who captained Scotland at this summer’s Under-17 European Championship in Israel, is a product of Killie’s academy and made his debut at 16.
McArthur moved to the Premier League outfit for an undisclosed fee and will go into the Magpies’ under-18 squad.
McInnes told Kilmarnock’s official website: “We understood, like all Scottish clubs, that we’re vulnerable to the richest league in the world with all the money that is available there.
“Ideally Charlie, as a Kilmarnock supporter, would have played 100 games for the Kilmarnock first team and we would have gotten a lot of satisfaction in seeing that.
“Unfortunately for us, a bigger club has come along and identified he’s a good player, which he is.
“The move was something that Charlie was keen on, so once we established that with his agents, then it was all about us getting the fee that we wanted, which thankfully we did.
“We wish Charlie all the best. He’s a great kid and he’s someone we’ve really been impressed with in the short time that I’ve been here.
“You can see exactly why Newcastle would want to bring him into their system and we’ll look out for him and hope he does well there.
“He will always be welcome back at Rugby Park.”
