Most chose to stay in the official player hotel, which ensures they are isolated and protected from the coronavirus. However, every player is afforded the option to rent a house in the "bubble" if they'd prefer a greater level of security. Former World No.1 Serena Williams opted for a rental home, citing her previous history of significant lung complications.

"I want to be here, but I have genuine health issues," Williams said Friday in a Zoom meeting with reporters covering the Western & Southern Open, which begins on Saturday. The tournament is a prelude to the US Open, which will begin on August 31st.

"I didn't want to be in the [official player] hotel because I have lung issues and felt it was a big risk for me personally," she said. "In a house, I can control more, there's no housekeeping staff, none of that stuff. I needed to put my mind at rest so that I could perform in New York."

Williams suffered a pulmonary embolism during labor before giving birth to daughter Alexis Olympia in September 2017. She endured a second one shortly the delivery, which left her bedridden for six weeks and delayed her return to training.

The USTA decided to allow players to stay with their families or entourages in private houses instead of one of the two approved tournament hotels if the players agreed to certain conditions. Those include a mandate to provide security to monitor the behavior and activities of those in the home during the three-plus-week period in which the tournament is being played inside a bio-secure bubble at the traditional home of the US Open.

"They have to guide you, make sure people aren't leaving, going to nightclubs and restaurants," Williams said of the mandate. "I think that's good, because people might get antsy and might want to go places. I want to know where people are going. I want to make sure we are all keeping ourselves in this giant bubble. There are more people now, with 128 draws. That's a lot of people, so I like to know that everybody is staying to their word and being honest about it."

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