Rafael Nadal is still not sure when he will return to action.

The 22-time Grand Slam champion has been on the sidelines ever since a hip issue contributed to this second-round exit at the Australian Open back in January.

Having since missed the Indian Wells and Miami Open, there was an expectation that Nadal would be back in time for the Monte Carlo Masters which commence April 8.

That was the case especially after the official tournament account tweeted that he would “definitely” be featuring.

That turned out to be news for the Spaniard who revealed he still doesn't know when he will play again as he couldn't confirm his participation in Monte Carlo.

“I'm following my course and I don't know when I'll play again, that's the truth,” Nadal was quoted as saying on Marca. “I'm in a phase of increasing work. If I knew when I was going to come back I would say so, but I don't know.

“I can't confirm that I will play in Monte Carlo, things are being seen day by day. I prefer to say things when I really know them.”

Monte Carlo marks the start of the clay-court season — Nadal's preferred surface — and is followed by events in Barcelona, Madrid and Rome before ultimately concluding with the French Open.

Nadal is an 11-time winner at Monte Carlo and notably won the tournament eight consecutive times from 2005 to 2012. While it would be a blow for Nadal to miss out, a consolation is he only made the quarterfinals last year so won't lose too many points.

However, every point will matter now — especially after his 18-year streak of featuring in the ATP top ten ended earlier this month.