Rafael Nadal concedes it is unlikely he will play tennis again in 2012.
Nadal has not picked up a racket since suffering a surprise second-round exit to Czech Lukas Rosol at Wimbledon in June.
Since then, the 26-year-old has missed the Olympic Games and US Open as he battles ongoing knee soreness.
"Impossible, no. But difficult, yes," Nadal said when asked whether he would make a comeback before the end of the season.
"I want to go day-by-day, I go every day to the gym, the swimming pool to continue with my recovery. I am trying not to think that far.
"It has been very, very tough for me because I feel that my knee didn't improve in the right way ... but the last couple of weeks the improvement in my knee is something that I can really feel.
"That helps me to keep working hard doing every day what I have do.
"I am working to try to come back to practice on the tennis court in a not very long period of time."
Nadal, an 11-time grand slam winner, has suffered his fair share of niggles over his career but very few long-term injuries and admitted he was unsure of how long this setback may persist.
"That is something I will know when my I feel my knee completely without pain when I start to practice," he said.
"I didn't have in the past this long period of time outside of the tennis court, outside of the competition.
"I can imagine when I come back I will need time to practice and practice more and more every day, maybe that will take one month and a half.
"The most important thing is to continue with the treatment ... when I don't feel nothing, hopefully that will happen soon, I will come back on the tennis court."