Spain's Rafael Nadal said on Wednesday that he is not sure if he will be able to play at next month's French Open after pushing through the pain barrier in his comeback from injury.

The 37-year-old, a 22-time Grand Slam champion, said that he is far from being in top form and that he is only playing against American Darwin Blanch in the first round of the Madrid Open on Thursday as a personal sacrifice.

"If I was in Paris today, I wouldn't go out to play," Nadal told a press conference, in reference to Roland Garros.

"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.

"This doesn't mean I'm giving up on anything in the next few weeks, I don't know what might happen. 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."