Perch is Chris Hughton's first signing in preparation for their Premiership return.
Clark told the Evening Chronicle: "I'm quite surprised Forest let him go.
"James came through the Academy system at Nottingham Forest, and he's a promising young player.
"He can play in a number of positions.
"He played left-back a lot last season, which isn't his favourite position. And he's just as comfortable at right-back.
"But he's more a midfield player, really."
Clark hopes that Perch can go on to fulfil his potential at Newcastle after becoming Chris Hughton's first signing of the summer.
And he went on to say: "No-one's guaranteed to be a success in the Premier League, but he's had a good upbringing at Forest, and perhaps he needs a move.
"He's been part of the furniture, and moving to the Premier League is fantastic for him.
"He'll be thrilled and I'm sure he's got a good chance of success with Newcastle."