The 29-year-old has already had surgery and will undergo chemotherapy to treat the illness, which was diagnosed post-season.

The club is confident he will make a full recovery and begin pre-season training in November.

In a statement Port's doctor Mark Fisher said further treatment was required to reduce the chance of cancer returning.

Gray finished fourth in the club best and fairest on Friday night after winning the club's previous three best and fairests.

Port's football manager Chris Davies pledged the club's support during Gray's recovery.

"Robbie's heath and wellbeing is, as always, the most important thing to us," Davies said.

"We are thankful the surgery went as well as it could have."

Gray is the second AFL player to be diagnosed with testicular cancer in 2017.

Melbourne's Jesse Hogan underwent surgery in May but recovered in time to return to football in July.

Gray has played 178 games for Port Adelaide.