"Dipa's rehabilitation is still going on and it will go on for some time now," Nandi told on Monday.
Dipa's rehabilitation after a knee injury has been taking longer than usual and that forced her out of the Asian Championships which took place in Mongolia last month, where Pranati Nayak clinched a bronze medal in vault event.
"We cannot do anything right now. We will act according to doctor's advice. I won't risk her unless she is completely fine. Once she is fine, I will consult the doctor and the physio," Nandi conceded.
The Tripura girl, who missed out on a medal by a whisker at the 2016 Rio Olympics, will now face an uphill task to be ready in time for the World Championships in Germany, starting October 4-13, which will serve as the qualifying event for the Tokyo Olympics.
Asked about a timeline as to when she can return to action with the Olympics less than one year to go, Nandi sounded non-committal.
"I can't say anything about her Olympics participation at the moment. It won't be fair for me to comment. I need to talk to the doctor first.
"I cannot tell you when she will return, I cannot give a tentative timeline. Like I said, her rehabilitation is still going on and it will go on."
Nandi remained hopeful of a comeback, nonetheless.
"But one thing I can tell you, we haven't lost hope yet. Now it all depends on the condition of her feet, doctor and physio. Even if there is one percent pain, we won't risk her," he added.
For gymnasts to seal an Olympics berth, the qualification system comprises eight World Cups. The top three in these events make the cut.
Dipa aggravated her knee injury while participating in the Baku World Cup in March. She has been recovering since then and could not take part in the World Cup in Doha, losing crucial ranking points in the process.
( With inputs from IANS )