Sam Docherty during Carlton's R9 clash with Melbourne on May 16, 2021. Picture: AFL Photos

CARLTON co-captain Sam Docherty will undergo chemotherapy after being diagnosed with testicular cancer for a second time.

The defender will undergo 12 weeks of chemotherapy, and is expected to make a full recovery in time for pre-season training next season.

The cancer is a secondary occurrence to a previous testicular cancer diagnosis, and was detected at a routine check-up.

Docherty previously underwent surgery to remove a malignant testicular tumour in late 2020.

"It's obviously not the news we wanted to hear but the support I have from everyone around me in my family, friends and the footy club will get me through this next challenge," Docherty told Carlton's website.

"I am very fortunate this secondary diagnosis was detected early as part of a routine check-up. We now have a clear plan in place to get through this.

"I really want to get the message out there of how important it is to be mindful of your health. If you feel something isn't quite right, please, get checked and make sure you look after yourself."

Carlton's Head of Football Brad Lloyd said Docherty would be well supported by the club.

"We will do everything we possibly can as a footy club to help Sam and his family through this," Lloyd said.

"Right now, Sam's health is the number one priority and he will be given all the support he needs as he undergoes the necessary treatment to allow him to recover fully.

"Sam is an incredibly resilient person, a strong character and the entire Carlton family is behind him every step of the way."