The final grand slam of the year is just weeks away and the tournament may go ahead without the 21-time grand slam winner Djokovic, due to his stance on Covid-19 vaccination.
Even after causing a furore in Melbourne at the Australian Open in January - where he was deported and effectively banned from the strict island nation - the Serb has stood firm on his anti-vaccination status.
Under the current rules, non-US citizens must be fully vaccinated against Covid-19 in order to enter the country. The US Open begins at the iconic Flushing Meadows on August 29, meaning Djokovic and his team are running out of time...
"Novak will do everything to be there, maybe he will get a special visa... but there are only two weeks," Ivanisevic told Italian news outlet La Repubblica.
"Personally, I have zero hope that [US President Joe] Biden will change the rules before the tournament starts.
"For me it is all nonsense and bull****. If you are vaccinated but positive you can enter the United States. If you are not vaccinated but negative, you are banned. There is too much politics in sports."
Meanwhile, Dr John Reiner told the Holding Court Podcast that the US' current Covid-19 policy no longer serves its purpose.
"Look, I think it's a bad take for Djokovic not to be vaccinated, I think it's a bad example," said Dr Reiner.
"I still think he should be vaccinated for his own protection, and his concerns about the safety of vaccines I think are unwarranted. The vaccines are extraordinarily safe and the risk to an athlete's health is much greater from the virus itself than it is from any potential vaccine.
"But having said all that, it seems like the United States policy, as implemented last October, has outgrown I think its usefulness to the public health."
The world number six has amassed a 25-6 record for the season so far, picking up the Rome ATP Masters 1000 title and most recently his 21st Grand Slam on the hallowed courts of Wimbledon.