The 38-year-old Nadal, who won his opening doubles clash alongside Carlos Alcaraz on Saturday, is due to face Hungary's Marton Fucsovics in the first round but has been playing with a heavily bandaged right thigh.
"The issue of the bandage is cumbersome, but it is also an issue of prevention," said Spain captain David Ferrer.
"We will see when the match is over how it evolves, but as I say, the important thing is that today he has warmed up, that he is ready to play."
On Saturday, Nadal had cast doubt on his participation in the singles, insisting he would "make the smartest decision that I can to have the best chance of bringing a medal home, so let's see."
Nadal, a singles gold medallist at the 2008 Beijing Olympics and doubles title-winner at Rio four years later, is playing just his seventh tournament of 2024.
Before suffering a thigh injury, he had also battled a hip problem and sat out Wimbledon.
Nadal has won 14 of his 22 Grand Slam titles in Paris but at 38, time is ticking for the Spaniard, who last month suffered his earliest exit from the French Open.
He is unseeded at the Games and a win over Fucsovics would pit him against top seed Djokovic in the second round, in what would be the pair's 60th meeting.
"Roland Garros is the most special place in the world of tennis for me," said Nadal, who won Olympic singles gold at Beijing 2008 and doubles gold with Marc Lopez in Rio eight years later.
