Nick Kyrgios says he has a new lease on life on court after being amazed at sudden improvement in his long-term knee injury and the Australian hinted at a Grand Slam comeback at Melbourne Park if he makes it through a series of exhibition matches.

The 2022 Wimbledon finalist has dropped to 652nd in the world after playing only six matches in three years due to a succession of wrist and knee injuries, and would need a wildcard from organisers to compete at the Australian Open in January.

"I don't know whether to call it a miracle or anything, but my knee feels like it's gotten younger by a couple of years," Kyrgios told the Australian Associated Press on Thursday.

The 30-year-old said that earlier in the year he was at the point where he did not have any hope of being able to play the Australian Open again, or getting back to the point where he felt comfortable enough with his body to compete.

"But something in the last month, I don't know what it is. I was with my masseuse and physio last night and something really has changed with my knee," he said.

"It's not swelling. It's not feeling bad after a session.

"I have a new lease on life on court. Honestly, I'm in a really good space at the moment and, physically, I've been putting in the work."

Kyrgios will play exhibition matches against Ben Shelton at the Atlanta Cup on December 6, and Tommy Paul at Madison Square Garden two days later, before facing Aryna Sabalenka in a "Battle of the Sexes" match in Dubai on December 28.

"Then if I get through all of that, I'm ready to go," said Kyrgios, who reached a career-high singles ranking of 13th in 2016 but has not played since losing in the second round of the Miami Open in March.

The Australian Open begins on January 12.