Venus, left, and Serena Williams are two of the over-30 stars on the WTA tour who would like some relief from playing required events, to help extend their careers. The men’s tour has different rules, some designed to do that. (Clive Brunskill/Getty Images)

For much of its 43-year history, the WTA celebrated pigtailed prodigies like Chris Evert, Tracy Austin, Monica Seles and Martina Hingis. Protecting young stars with age-related restrictions became a priority when too many fell victim to injury, burnout or early retirement.

Now the women’s tour may have the opposite problem: Safeguarding its aging assets.

With increasing purses — Saturday’s female French Open singles champion will earn more than $2.2 million in prize money — and better physical preparation, women are playing longer and more successfully than ever before.

There were no matches played at Roland Garros on Monday. Steady rain led to the cancellation of all play, the first washout in 16 years at the French Open. Organizers said matches would be rescheduled for Tuesday, but forecasts call for more rain.

The WTA has in general trailed the ATP Tour when it comes to schedule-reducing options for all players. Serena Williams, the defending Roland Garros champion and at 34 the most successful 30-something in WTA history, said more could be done to relax mandatory tournament commitments for long-term veterans.

“I mean, it’s a no-brainer,” the top-ranked Williams said.

Williams cited fellow 34-year-old Roger Federer, who under ATP rules has been able to skip some mandatory tournaments in recent seasons because of his longevity.

“Roger’s been playing for years,” said Williams, a 21-time major winner who turned pro in 1995. “It helped his career. It definitely should be an option. You shouldn’t have to play every week.”

“I think it should be addressed,” WTA founder Billie Jean King echoed in an interview this spring. King said she would like to see women “stay in the game longer.”

Both the ATP and WTA tours require players to participate in different tiers of events to ensure the importance of top-level tournaments and also to protect the viability and entertainment value of smaller events.

On the men’s tour, any player above the age of 30 who has played 12 years or 600 matches can opt out of one of the tour’s eight mandatory events. They can do this without risk of penalty, such as exclusion from a bonus program or ineligibility for future tournaments.

Any player meeting all three conditions (30 years old, 12 years on tour, 600 matches) can skip all mandatory events, a benefit enjoyed by Federer, who declined to enter the Miami Masters 1000 in two of the past four years.

Twenty-nine men, including 31-year-old defending French Open champion Stan Wawrinka, fall into this category.

Under WTA rules, only players older than 30 and ranked in the top 10 can avoid certain tournament commitments. The tradeoff: They can’t participate in the tour’s year-end bonus pool.

The vast majority of women, regardless of years on tour or matches played, can’t opt out of tour-required events, of which there are four.

Venus Williams, a seven-time major winner, is one of two players who chose not to participate in 2016.

“For me, it made sense to do what I needed to do and play at the pace that works for me,” said Venus, who turns 36 next month and suffers from the energy-sapping immune disease Sjogren’s syndrome.

Venus, who like her younger sister Serena sits on the WTA Player Council, said she would like to see additional age-related thresholds for the entire tour, just like the men’s.

“If you have big stars in the sport, you want to keep them around as long as possible,” she said last week before defeating Alize Cornet of France on Saturday to reach the French Open’s fourth round for the first time since 2010.

Women’s tennis was once considered too hazardous for the young. Populated by a growing cadre of teenage phenoms, the WTA enacted age-eligibility rules in 1995 that limited the number of tournaments players between the ages of 14 and 17 could enter.

The rules came to be known as the “Capriati Rule” after the precocious success of American Jennifer Capriati.

Capriati took the tour by storm at 13 but left in a swirl of adolescent ignominy, including arrests for shoplifting and marijuana possession. She later returned and won three Grand Slam titles.

Tennis’s graying trend has been going on for years, for men and women. Fewer teenagers have been able to break into the top 100 because of the increased physical demands and all-around professionalism on and off the court.

At Roland Garros, 19 women aged 30 or older were entered in the 128-player singles draw, a record across all Grand Slam tournaments in the post-1968 Open era.

The men also set a new high in Paris: 51.

Mature women are reaching the pinnacle of the sport more frequently. In the Open era, nine players past their 30th birthdays have won a total of 22 majors, but nearly half of those occurred in the past four years.

China’s Li Na was 31 when she won the 2014 Australian Open. Italy’s Flavia Pennetta was 33 when she captured last year’s U.S. Open.

Serena, the oldest No. 1 in WTA history, has won an unprecedented eight majors since she finished her third decade.

The last teenager to win a Grand Slam was 19-year-old Maria Sharapova at the 2006 U.S. Open.

It can be tricky to compare the complexities of WTA and ATP rules. They operate independently, with differing tournament commitments, bonus pools, wild cards and other day-to-day nuances.

Steve Simon, chief executive of the WTA, said he was comfortable with current age rules.

“We think this is already a very straightforward and progressive approach that enables each player complete flexibility to design a schedule beneficial to her around those four events — along with the Grand Slams, which aren’t under the WTA’s purview,” Simon said in an emailed statement.

“We want to keep our players in the game and encourage them to keep competing into their 30s and will continue to look at and reevaluate the rules as appropriate,” he added.

Some veterans agree.

Italy’s Roberta Vinci, 33, who denied Serena a possible calendar-year Grand Slam in the 2015 U.S. Open semifinals, said that players are astute enough to manage their own schedules.

“I prefer to play without rules,” Vinci said.

The Williams sisters said they intend to bring up the topic at future Player Council meetings.

“It would be nice to have options, especially at the end of the year when everybody is pretty much bandaged,” said Venus, who has logged more than 900 singles matches in her 22-year career. “I’m going to look into it, actually.”

Chris Evert said she “loved” the idea of additional protections.

But Evert, who won two of her 18 major titles after she had turned 30 and retired in 1989 at age 34, puts some of the blame on players themselves.

“The women are just off in their own little cliques,” she said. “They’ve got to get together and voice their opinion if they want changes. In our era, the top players always got their way.”