Rafael Nadal said he will only play at the upcoming French Open if he feels "capable enough to compete well."
"I don't know what's going to happen in the next three weeks. I will keep fighting and doing the things I believe so I can try to play in Paris," the former world No 1 and 14-time French Open winner said at the Madrid Open.
"I will not play in Paris if I am the way I am now. I wouldn't take to the court. I will only play in Paris if I feel capable enough."
Nadal, 37, returned to tennis in Brisbane in January after almost an entire year nursing a hip injury. But his comeback was short-lived as he sustained a muscle problem in Australia and has competed in just five matches this season.
The Spaniard kicked off his clay campaign in Barcelona last week, where he lost in the second round.
"A few weeks ago, I didn't know if I will be able to play again on the professional tour," he added.
"It's not perfect ... I'm able to enjoy the fact that I can say probably goodbye on court."
Nadal says he's hitting the ball well when on court but "it's about more body limitations."
Meanwhile, Naomi Osaka said she was "embracing the clay a lot more now" as she captured her first victory on the surface since 2022 in the Madrid Open first round.
The Japanese grew up playing on hard courts in the United States and has mostly struggled on the red dirt, but she looked comfortable during her 6-4, 6-1 win over Belgian lucky loser Greet Minnen.
Fellow former US Open champion Emma Raducanu was not as fortunate as the Briton fell 6-2, 6-2 to Argentinian Maria Lourdes Carle.
Rafael Nadal is still not at 100 percent as he continues his comeback from injury. REUTERS