American John Isner, ranked 25th in the world, said Monday he won't play the Australian Open because of Covid-19 restrictions at tennis's first Grand Slam of 2021.

"At this stage in my career and in my life, I've always had visions of being able to travel with my family. And of course, that wouldn't be the case for Australia this year," Isner said after falling to fellow American Sebastian Korda in the quarter-finals of the Delray Beach Open in Florida.

Australian Open organizers have instituted strict quarantine requirements for players who want to compete in the tournament beginning February 8.

"I get it," Isner added in comments that were posted on the Tennis.com website. "It really was just a situation where I didn't want to be away from my family for that long. So, I've decided to stay home."

The 35-year-old father of two said he didn't yet know just what 2021 will hold for him.

"I have a super-long break right now, that's for sure," said Isner, who added he only made his decision to skip the Australian Open on Sunday night.

"It wasn't an easy decision at all," he said. "I thought long and hard about it. But I feel comfortable with my decision right now and looking forward to getting home."