World No. 19 Grigor Dimitrov is another high-profile player who is uncertain of his participation at this year's US Open, which is scheduled to begin on August 31 in New York.

With the number of COVID-19 cases rising in most parts of the United States, it comes as no surprise that most players are concerned about their health. The sentiment resonates strongly with the Bulgarian, as he tested positive for the coronavirus during the Adria Tour a few weeks ago.

"Right now, I'm very uncertain, I'll be completely honest," he said. "I thought about it and I keep thinking about it every single day. I feel like there are so many questions I have to ask and there are so few answers.

"I've had it, so I know what it is. For Europeans, it's hard because you have got to travel about 12 hours to get to New York and take a couple of planes, then get to a hotel, and the bubble is a bubble, but I mean statistically we're like over a thousand people in the same place and it's just not easy.

"I hope nobody gets it but if somebody gets it things are going to look a little more complicated. Even if we have agreements from governments with quarantine and everything, we just never know what will happen from one day to another so it puts a lot of limitations on the schedule and yourself because you want to complete."

Furthermore, Dimitrov is concerned about the rigors of playing Grand Slam tennis after having just recovered from the virus.

"I've been on the mend, practicing a lot more, feeling like I have more energy and more of everything, but there's still a question mark," the Bulgarian said. "Right now it's such a delicate time that I cannot say 'yes, I'm going' or 'no, I'm not."

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