CARLTON players are in for a hair-raising Friday, shaving their heads as a fundraiser for the Peter Mac Cancer Foundation and in support of teammate Sam Docherty.

The co-captain is undergoing chemotherapy after a secondary testicular cancer occurrence in two years.

Docherty took to Instagram on Tuesday to declare he is "feeling great" after the first half of his treatment.

Blues co-captain Patrick Cripps wrote on the fundraising page to call for more people to join in.

"One of our own, Sam Docherty, is currently fighting a battle and as a club and broader community, we are wanting to show our support for him and the Peter Mac Foundation," he said. 

"On Friday 8 October, please join a number of players as we shave our heads in support for Sam.

"We will post before and after photos plus videos, and we would love for you to do the same and tag the Carlton Football Club and the Peter Mac Foundation.

"We also want to raise funds for the Peter Mac Foundation to support their discovery of cancer cures. We are hoping to raise $5,000.

"Thank you in advance for your generosity, and we can't wait to see a few shaved heads getting around in support."

Sam Docherty and Patrick Cripps lead Carlton out against Essendon in R7, 2021. Picture: AFL Photos

The Blues have already smashed their initial goal, raising $16,000 in less than a day. Donations can be made here.