The Spaniard, who has said he expects to retire after the 2024 season, returned to competition in Brisbane in January after almost a year sidelined with a hip flexor injury.
He was then out for another stretch due to a thigh issue and while he returned in Barcelona last week he says he is far from being in top form and does not know if he will play in next month's French Open.
Nadal beat wild card Darwin Blanch 6-1 6-0 in the first round of the Madrid Open on Thursday, with his wife and one-year-old son Rafael Jr watching on.
"Well, I would love to play a little bit longer and give him a memory of myself playing tennis," Nadal said of playing in front of his son.
"That's what will be the ideal thing for me and for my wife and family. Probably I will not be able to make that happen.
"But at least I’m happy to have a great team and family and friends around me during all my life that helped me in every single way of being happy."
Nadal, a five-time champion in Madrid, next faces Australian 10th seed Alex de Minaur on Saturday.
