Nadal suffered his first defeat at a grand slam in 2022 as the Australian Open and French Open champion struggled to hit top form following an abdominal injury that forced him to withdraw from Wimbledon and disrupted his preparations for the final major of the year.
Nadal is scheduled to play at the Laver Cup in London later this month, along with Roger Federer, Novak Djokovic and Andy Murray, but that now appears to be in question.
The Spaniard’s wife is expecting their first child back home in Majorca and has reportedly experienced complications with the pregnancy.
And Nadal said: “I need to go back. I need to fix things, life, then I don’t know when I’m going to come back.
“I’m going to try to be ready mentally. When I feel that I will be ready to compete again, I will be there.”
Nadal played down his disrupted build-up to the US Open after Tiafoe completed a 6-4 4-6 6-4 6-3 on Arthur Ashe, in the biggest win of the American’s career.
“Of course, this was not the ideal preparation for me,” the 23-time grand slam champion said.
“We can’t find excuses. I have been practising well the week before, honestly. But then when the competition started, my level went down. For some reason, I don’t know, mental issues in terms of a lot of things that happened the last couple of months, maybe.”
Nadal’s exit throws open the men’s draw and means there will be a first-time grand slam winner. There will also be a new men’s world No 1 if either Carlos Alcaraz or Casper Ruud reach the final.