Newcastle Jets coach Gary van Egmond believes new signing Angelo Costanzo will be behind in fitness when he links up with the team on Monday.

Costanzo is currently finishing his time at Adelaide United and is expected to be a substitute in Saturday night's grand final but van Egmond says a lack of game time in recent weeks will have the key defender catching up in the fitness department.

"I suppose the hardest thing for Ange will be the fact that he hasn't played a lot of football in regard to game time with Adelaide," van Egmond said.

"He's also coming here late, which makes it a lot more difficult for him to get a starting position.

"Realistically, he's a victim of circumstances with all that.

"It's a difficult one because he just hasn't had games, and there's nothing like match fitness."