Since returning from his injury last month, Nadal has won 12 of 13 matches in a South American clay-court swing, finishing runner-up in Vina del Mar, Chile, before taking titles in Sao Paulo and at the Mexican Open.
"Today I know I can play on clay. I will try next week on the hard," Nadal said. "Playing tennis will be a process to adapt my knee to the competition.
"I hope I will keep having the chances to play the normal calendar as I did in past years.
"I cannot predict the future. I have to see how the knee will last at Indian Wells next week. Having the chance to play at Indian Wells is great. I didn't know one week ago if I would be able to play at Indian Wells."
After Indian Wells, Nadal could play at a hardcourt event later this month at Miami, then switch to clay ahead of the French Open and grass for Wimbledon before facing hardcourts again in the run-up to the US Open.
Nadal, set to play an exhibition match against Juan Martin del Potro on Monday in New York, said his knee has improved for the past couple of days.
"I go day by day," Nadal said. "After seven months with a lot of pain in my knee, I don't have the chance to decide which one will be my schedule for the future. I try to enjoy every one."
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