Carlton has been rocked by news Matthew Kreuzer will have knee surgery and miss up to a month.

The Age has revealed the ruckman damaged his meniscus in the first half on Sunday against Port Adelaide.

"The scans confirmed our suspicions and he will have surgery and miss three to four weeks," Carlton football manager Andrew McKay said.

"He did it in the second quarter. We were confident he had done it and it is one of those injuries where you are not going to do more damage so if you can play with the discomfort you can play on.

"To get back out there and do what he did was just a fantastic effort he didn't just get out and play he led and have a big impact, he dragged players along with him.

"You can't speak highly enough of his performance it was very impressive courage and strength to play on in pain and have such a big impact."

Carlton will already be without fellow ruckman Andrew Phillips with a hamstring injury and key forward Levi Casboult with a knee.

It means Daniel Gorringe or Cameron Wood could come into the side to take on the Roos on Saturday night.

Earlier scans cleared Patty Cripps of serious damage to his knee and Carlton is confident he will play.

Rising star Jacob Weitering may miss another week as he recovers from a shoulder injury.