The City chief was thrilled to get the centre half’s signature on a new deal this week – the first of the club’s out-of-contract players to pledge their future to Valley Parade.
McArdle, who has played 99 games for the club, has been a mainstay in City’s rise over the past two seasons and formed a solid partnership with Andrew Davies.
And Parkinson believes the Northern Ireland international, who was 27 at the start of the month, will continue to get better.
He said: “Rory has played a big part for us last year and this, he’s a full international, and he’s a player I’m expecting to keep improving. He’s very consistent.
“At his age, centre halves reach their peak in the next three years. I’m delighted that’s going to be with us.
“Last season was the first time he’d played in League One. He’d been in Scotland and in the bottom division but this was going up a level.
“Suddenly you’re faced with more intelligent strikers posing different problems. It’s been a learning curve for Rory but he has improved.
“There are still areas of his game he can work on but I’m sure he will do that. He has got the right attitude to keep getting better.
“He is also ambitious, he wants to keep moving upwards and hopefully he can achieve that with us.”
Davies was the only regular in the back four not out of contract this summer. While City wait for Stephen Darby and James Meredith to mull over their offers, they at least have their first-choice central pairing in place.
City boasted one of the tightest defences in League One last season and Park-inson believes the middle duo were a cornerstone of that.
He said: “The record when those two play together is outstanding. I wanted to keep that in place.
“It’s not often you get centre halves with the athleticism that Rory has got. It’s so important to have his mobility in the back four.
“He’s a really good character and a great lad off the pitch as well. He’s good to have around the training ground and the type we want to have in the squad.”
McArdle appeared 43 times last season, scoring twice, and also established a regular spot in Michael O’Neill’s international squad.