Carlton forward Harry McKay is unavailable for Sunday’s blockbuster King’s Birthday Eve clash against Essendon due to knee sore soreness.

It will be the fourth game this season that the 27-year-old has missed with the club making the call after the captain’s run on Saturday morning.

McKay - who has missed games earlier this year due to personal reasons - returned to the club after the bye and trained alongside the rest of Carlton’s squad last Saturday morning.

Know the news with the 7NEWS app: Download today

But he was absent from main training earlier on Thursday.

On his podcast Ben and Harry on April 10 — co-hosted by his brother and Essendon defender Ben McKay — Harry opened up on the reasons behind his period of personal leave during the year.

Harry shared details about his wellbeing, saying he was “not in a great place mentally” during the off-season.

“That progressed, then unfortunately feeling in a worse and worse spot. I felt like I had to put on a bit of a facade to pretend to be OK when I really wasn’t,” he said.

“It got to a place where I had to put my hand up and say I needed some help.”

Hudson O’Keeffe, 20, will now make his debut for Carlton on Sunday night in front of a crowd that could exceed 75,000.

The 202cm forward-ruck was a supplementary selection period signing ahead of the 2023 season.

He will be Carlton’s seventh debutant this year.

“You’ve worked really hard,” Voss said to O’Keeffe while announcing his club debut.

“The thing we love about you the most is it’s not about the kicks, marks and handballs - it’s going to be about how you compete. That’s your real strength - these guys will love playing with you over a long period of time, I know it.

“They’re going to be talking about how you compete, how you protect people... congratulations mate, you’re going to live out your dream.”

More to come ..