Huxley, who recently signed a new contract until 2010, will undergo an operation next month to remove the tumour that was revealed in an MRI scan following the game against the Reds on March 1.
ACT Rugby Union chief executive Andrew Fagan reassured Huxley that the Brumbies and the Australian Rugby Union would honour his contract, although he is not ruling out a return for the Australia back.
"There's still faint hope," Fagan told the Australian.
"You never know what might come out of the surgery. The doctors could give him the all clear to resume playing. We're resigned to the fact that he won't play again but we don't want to have that conversation yet. There's no rush."
The Brumbies, though, are keen to secure a replacement with the versatile Shepherd, who has won six caps for Australia, heading the list.
Western Force chief executive Mitch Hardy confirmed the Brumbies have lodged an interest in Shepherd, however, they face an uphill task of luring the player away from Perth after he revealed last week that he was set to sign a new deal "in the next two weeks".
Hardy confirmed the full-back was set to reach a conclusion on a new contract in the near future, saying: "Hopefully, Cameron will decide on his rugby future in the next couple of weeks."