Rafael Nadal will not play his scheduled doubles match at the Brazil Open on Wednesday because of "knee overuse," organizers said.
But they said the Spanish star intends to play his opening singles match Thursday against Brazilian Joao Souza.
World number five Nadal had been scheduled to team up with Argentina's David Nalbandian in a second-round encounter against Argentine Horacio Zeballos and Oliver Marach of Austria.
Former world number one Nadal only returned to the tour in Chile last week, where he lost in the final, after a seven-month injury absence.
"Nadal thought it was preferable to stay in his hotel and prepare for his singles match tomorrow," a Brazil Open spokesman told AFP.
"He discussed the issue with Nalbandian and the two agreed not to play the doubles. It was a joint decision."
Nalbandian told reporters the conditions were "very difficult."
"The court is not in the best condition and the ball is very difficult to control," he added.
"It's too bad I cannot play the doubles after the match Rafa and I had (yesterday)... But he has to take care of himself and prepare for a long and hard year."
Nalbandian and Nadal won a hard-fought match 6-3, 3-6, 11-9 against Spaniards Pablo Andujar and Guillermo Garcia-Lopez on the court here late Tuesday.
Nadal complained at a press conference Tuesday about having to play so many hard court events.
"That is a theme among the players and doctors," he said.
While conceding that reducing the number of events on hard surface was not possible at this time, Nadal added: "I think that the ATP has to work to think of how to lengthen tennis players' careers."
"Can you imagine football players playing on cement?" he asked.
"I am a bit tired after a hard week in Chile. But it was positive. The process of recovery follows its course... As always I come here to do the best possible and hope that things turn out all right."
Asked when he expected to be 100 percent fit, Nadal said: "I cannot know the future."
"If my knee allows, I will do everything possible to be at my best," he added.
"I am a player who plays with a lot passion, a lot of energy. I suppose that does not help the knee."
The 11-time grand slam champion, who lost both the singles and doubles finals Sunday at his comeback event in Vina del Mar, Chile, is the top seed at this week's event here.
The $455,775 Brazil Open is part of the Latin American clay court circuit, along with the Vina del Mar and the Mexico Open in Acapulco where Nadal plans to play later this month.
The three events are routinely ignored by the world's top three players: Novak Djokovic, Roger Federer and Andy Murray.
Nadal won the Brazil Open in 2005 when it was held in Costa do Sauipe in eastern Bahia state. The tournament was moved to Sao Paulo last year when Spaniard Nicolas Almagro won.
Asked about Nalbandian's complaints about the quality of the Sao Paulo court, Daniela Giuntini, a spokesperson for the Brazil Open replied: "Some players complain, others don't."
"Early this week, some were complaining that the court was not adequate for play. But as they played, trained, gradually they found that they were getting used to it. It was better. It's a process. There were the same complaints about the court in Vina del Mar," she added.
Menawhile Nadal said Tuesday that he plans to play in the 2016 Summer Olympics in Rio, adding that it would likely mark his last time at the games.
Considered by many to be the best ever clay court player, Nadal was back in Chile last week for the first time since a surprise second-round exit at Wimbledon in June.