Kei Nishikori, the 2014 US Open runner-up, said on Friday that he tested positive for COVID-19 a second time.
Nishikori wrote on his official mobile app that he will take another test next week, “at which time we will update you with more information.”
"I have very minimal symptoms and am staying in full isolation,” Nishikori wrote Friday.
The Western & Southern Open starts Saturday, while the US Open will begin August 31.
The 30-year-old Japanese tennis star has been ranked as high as No. 4 and is currently No. 31, which puts him in line to be seeded for the US Open.
Nishikori lost in the 2014 final at Flushing Meadows to Marin Cilic and was also a semifinalist in New York in 2016 and 2018.