PORT ADELAIDE co-captain Tom Jonas is a late out for the clash with North Melbourne on Friday night at Adelaide Oval.

Jonas suffered a minor calf strain at training on Wednesday and was given up until the last minute to prove his fitness but the club decided to take a conservative approach with the key defender.

Jonas has been replaced in the side by Jarrod Lienert, who will play his first game in the senior side since injuring his knee against North Melbourne in the JLT Series.