Serena Williams’ quest for the record books has been well documented. Unquestionably one of the greatest to ever pick up a tennis racket, after winning the Australian Open in 2017 while pregnant, Williams was one major away from tying Margaret Court’s record 24 Grand Slam singles titles.

Then came the hiatus. Williams missed four Grand Slams before her comeback, but in 2018 she reached the fourth round of the French Open and then the finals at Wimbledon and the U.S. Open. In eight attempts, she has reached four finals.

She remains so close to that record. It always seemed inevitable that she would reach it.

And now, as her runway to that milestone shortens at age 38, the tennis world and sports at large are taking a necessary pause. Although this means different things for athletes at different stages in their careers, for Williams and Roger Federer, it might put some goals too far out of reach.

“They won’t have 20 more opportunities,” Hall of Famer Martina Navratilova said. “They’ll have a couple more years and then Father Time will catch up with you and that goes for Serena and Roger but also Novak [Djokovic] and Rafa [Nadal].”

An era of tennis populated with a mix of greats and younger talents could reach a premature end.

Bit by bit, the spring sports calendar is eroding as an effect of the coronavirus pandemic. This past week, Wimbledon officials announced the tournament will be canceled for the first time since World War II. The French Open was rescheduled from late spring to September. In New York, the indoor space at the USTA Billie Jean King National Tennis Center is being converted into a temporary hospital for coronavirus patients.

The U.S. Open is not canceled. Yet the idea the hospital beds will be empty by Aug. 24 when the tournament is set to begin, or for the qualifying tournament the weeks before, seems increasingly unrealistic.

No less a legend than King said the decision to convert the facility was absolutely suitable given the circumstances. She has always stood for equity and access, even though that means something different here.

But for players such as Williams and Federer, what were short-term goals are now medium-term goals, if not longer.

There is a rhythm to the tennis year. Small tournaments lead to big ones. Training regimens put players in peak physical shape leading into May and late August. An athlete doesn’t usually stay in top shape without a tournament on the horizon, without a training goal on the calendar.

“If I’m Serena or Roger and I want one more Slam and I’m on hold, I kind of liken it to being in a rain delay,” Navratilova said. “You know you’re going to play again, you just don’t know when. You have to eat just enough, rest just enough to stay fresh for the match.”

Rest can be good for veteran players. Federer recently had knee surgery and was set to miss the French anyway, but not like this.

“There is a rest period,” Navratilova said, “but not knowing is weird, and you don’t have a timeline.”

Athletes at the moment are dealing with the same concerns and uncertainty as the rest of us. What is their income going to look like with cancellations? How do you protect your family? Wealth and fame offer insulation, but it isn’t complete.

A separate challenge is keeping up the hunger for another major. Both Williams and Federer are likely getting a sense of what life after tennis will look like. They may be able to spend more time with their kids — Williams’ daughter, Olympia, is now 2, and Federer has two sets of twins, ages 5 and 10.

It is hard to know what tennis will look like when it gets back. Air travel might have new restrictions, travel between countries might require health certification or quarantine, and competitions still may require same-day testing for staff and players. Will sponsorships still be there? Will tournaments still be in business? Will cities have the tourism core intact enough to host tournaments?

All that is out of the control of Williams and Federer. But they will likely face a bigger question: If there is a six-month hold on the sport, or longer, will every player return with the same mind-set with which they left?

“Billie Jean always said, ‘Champions adjust,’ ” Navratilova said. “This is what you have to do.”