The Covid-19 protocols proposed by the US Open organisers are "incredibly difficult" and would probably not work for World No.2 Simona Halep, according to her coach Darren Cahill.
The hard court Slam is scheduled to begin on August 31 and men's World No.1 Novak Djokovic has already said it would be "impossible" to play under the protocols, which would restrict players to their hotels with only one support staff.
"The restrictions are tough. They're incredibly difficult, and every player will have their own opinion as to whether that will work for them. I'm pretty sure that won't work for Simona," said Cahill.
"If you're in a football team, at least you have your team-mates to travel with, to socialise with and to eat with and to train with. Tennis is a little bit different because it's an individual sport."
Cahill said organisers were considering flying players to New York from around the world on charter flights and keeping them in an isolation bubble with regular testing for Covid-19.
"From Simona's point of view, you've got to fly over from Romania, you need to spend four weeks in this one hotel in New York, and you can only bring one person," said the Australian.
"Normally you have a physio, a hitting partner, trainer and maybe a coach or two. You've got to basically stay in this bubble with only one person for four weeks, and you have to be professional and compete at the highest level.
"So there are going to be a lot of players that have an issue."
Married players, particularly those with young children, would also have problems, Cahill (54) added.
A highly respected coach who guided Lleyton Hewitt to the top and also worked with Andre Agassi, Cahill has his "fingers crossed" the Covid-19 situation will improve sufficiently to make such protocols unnecessary.
"A lot changes in two or three days, let alone six or seven weeks. So I think a lot of the restrictions will start to come down," he said.