Novak Djokovic
Djokovic's return date remains uncertain as his injury hell continues. Getty Images

Former world number one Novak Djokovic is ramping up his recovery from injury, yet a timeline regarding the Serbian's return to tennis remains uncertain.

The 30-year-old confirmed last week that he had undergone a "small medical intervention" in the wake of complaining about a long-running elbow problem that has dogged him for two years.

Djokovic missed the final six months of the 2017 season with the injury, but returned last month to reach the fourth round of the Australian Open – where he lost to Hyeon Chung.

Twelve times a grand slam champion, Djokovic had treatment on the blow during the loss to the South Korean and admitted afterwards he would "reassess everything" regarding his physical well-being.

Swiss publication Blick last Friday (2 February) reported that Djokovic had undergone surgery on his right hand injury – rather than his injured elbow – and pictures later emerged on social media of the area heavily bandaged as he left Rennbahnklinik, a clinic know for orthopedic and rehabilitation expertise.

He later admitted via Instagram to having taken steps to achieving "full recovery", but refused to confirm whether he had indeed had an operation.

Now he has used social media again to provide an update as to his rehabilitation, posting a video showing him going through a range of movements with both arms using a resistance band.

The former Olympic bronze medallist is also seen wearing strapping on his troublesome right arm, the same arm band he wore during his ill-fated campaign in Melbourne. The post includes the message: "A big thank you to everyone for the support I've received since Friday's announcement. Looking forward to sharing my rehabilitation and progress!"

Though the latest video posted by Djokovic shows him without any strapping on his hand, the mystery behind the procedure and his insistence not to reveal the full extent of it has led to uncertainty over the timeline regarding his return to the sport.

Djokovic is not officially scheduled to return until the BNP Paribas Open in Indian Wells held on 5-18 March, having been named on the entry list last month alongside defending champion Roger Federer, but it remains to be seen whether he competes in the opening ATP World Tour Masters 1000 event of the season.

As Djokovic continues his recovery, he has found an unlikely ally in the form of Rafael Nadal's uncle Toni Nadal, who has called on the sport's authorities to take notice of tennis's lengthening injury list.

Nadal himself limped out of the Australian Open with a hip problem while Andy Murray has not played since Wimbledon last year due to a hip issue of his own that has required surgery.

"Tennis is a very tiring sport. We saw in the last [few] years and in recent times," Toni told Television Espanola, via Tennis World USA. "Many players got injured. In 2017, at the ATP Finals in London, five of the best players weren't there due to injuries, and the sixth, Rafael, got injured there.

"It's too much. Now we see Murray who underwent surgery, Djokovic with issues. They should do something. You have to ensure that the game is not that aggressive for players."