The 29-year-old winger, who was part of the All Blacks' 2015 World Cup-winning squad, has been battling a long-term knee injury and underwent surgery last year.
Naholo last played for the London Irish in the English Premiership in February 2020, before suffering what many feared could be a career-ending injury.
In an interview with Rugby Pass, London Irish coach Declan Kidney revealed that Naholo recently made his return to the field for the second-string team.
Kidney said he was hopeful that Naholo could return to his best and commended the 26-test All Black for the way he handled his injury and rehabilitation.
"If somebody was to write a book about rehabbing [an injury] I would be interested in his," Kidney told Rugby Pass.
"Sometimes when you see a player on the pitch it comes down to talent, but professionalism is about how you go about your job and stick to the task. The way he has gone about his would show any player the way back, and it hasn't been easy for him – but I haven't heard a word of complaint out of him."
Kidney said Naholo would be slowly transitioned back to the first team, following his successful comeback with the development side.
"It was a case of getting it right, and he has worked as diligently as anyone I have met," Kidney said.
"You don't ever want to see a player in that position. In adversity, you see the best of people and I cannot speak highly enough of him. He never dragged his arse about the place or felt sorry for himself, never acted the victim.
"He is not a guy to steal the limelight and he has helped the back three in training.
"It will be a little bit longer but the A-game was a stepping stone that we didn't advertise, and it was great to see him back out on the pitch – but we have a duty of care. We have to make sure we don't overextend him after such a long period out. He was the most senior player in the game."
