Rafael Nadal has heightened speculation that he will opt not to defend his US Open title by practising on clay rather than focusing on hard court preparations.
The ATP Tour is set to resume in August with a US hard court swing culminating in the US Open in September.
Before that is the Citi Open, which he has already opted to skip, and the Cincinnati Masters.
However, the European clay season, which was postponed due to the coronavirus pandemic, will take place immediately after the US Open.
Coach Carlos Moya has previously suggested that Rafael Nadal may not be able to do both sections of the tour due to requiring rest given he is now 34-years-old.
That prompted speculation that Nadal would pick just one, and he is always likely to choose his preferred clay, particularly given his dominance at, and affinity with, Roland Garros.
He has now heightened that speculation by resuming his practice routine on clay, suggesting that he is not preparing for the very different hardcourt challenges of the US Open, which he won last year.
Further concerns have been raised by many players that should they play the US Open, they would be forced to quarantine for two weeks upon their arrival in Europe, forcing them to miss the Madrid Masters and Rome Masters.