Rafael Nadal says he will only play at the French Open next month if he feels "capable enough to compete".
Spaniard Nadal, a 14-time champion at Roland Garros, missed the French Open for the first time in 19 years through injury in 2023.
The 37-year-old has indicated he plans to retire after the 2024 season.
He is set to make a farewell appearance at the Madrid Open this week and faces American 16-year-old Darwin Blanch in the first round on Thursday.
"If I was in Paris today, I wouldn't go out to play," Nadal said.
"I don't think I'll be able to play at 100% but it's important to be able to play for the last time in Madrid. It means a lot to me to play on this court where I've had some great moments."
Nadal made his most recent comeback from injury following a three-month absence at the Barcelona Open last week, winning his opening match before losing to Australian Alex de Minaur.
The 22-time major winner has only played five matches since January 2023 because of hip and abdominal injuries. A former world number one, he is currently ranked 644th.
The French Open, the second Grand Slam tournament of the year, starts on 26 May.
"Few weeks [ago], I didn't know if I will be able to play again on the professional tour. It's not perfect but at least I am playing and I can enjoy again, especially in the tournaments that are so emotional for me. I'm able to enjoy the fun that I can say probably goodbye on court," Nadal said.
He added: "Without trying to confuse anyone, I don't know what's going to happen in the next three weeks.
"I'm going to do the things I have to do to be able to play in Paris. And if I can, I can and if I can't, I can't. I'm going to Paris if I feel like I'm good enough. I'm going to Paris if I feel capable enough to compete."