In a move validating the surging popularity of women’s basketball, the WNBA says it will expand by five teams over the next five years. But as the league looks to the future, players are already concerned about a grueling schedule with minimal recovery time between games, leading to performance dips and injuries to rising stars like Caitlin Clark and Paige Bueckers.

Ms. Clark and Ms. Bueckers missed games over the weekend with injuries and remain day-to-day.  They are also in a notable group of players mired in shooting slumps that some blame on playing too many games in too few days.

A Los Angeles Sparks guard, Kelly Plum, responded to a post pointing out that Ms. Clark is not the only prominent WNBA player enduring shooting woes. Ms. Clark, college basketball’s all-time scoring leader, is 1-of-23 from three-point range in her last three games. Ms. Bueckers was 2-of-17 in her last five games. Entering the weekend, guard Marina Mabrey of the Connecticut Sun was 2-of-17 in her last three, while Ms. Plum was 4-of-22 in her last four.

“Cause we’re tired,” Ms. Plum posted.

The WNBA, which announced the latest expansion Monday, grew to 13 teams this season with the addition of the Golden State Valkyries. Although the regular schedule was expanded to 44 games from 40, the length of the season was not expanded, leaving less recovery time between games.

Players have expressed their frustration several times this season, with Satou Sabally of the Phoenix Mercury accusing Commissioner Cathy Engelbert of being irresponsible. “Cathy added a lot of games,” Ms. Sabally said after the Mercury played nine games in 18 days. “And us as players, recovery is so important. We put our bodies on the line every single time. We had nine games in 18 days. It’s not really responsible for a commissioner.”

Natasha Cloud of the defending champion New York Liberty was more pointed. “Cathy needs to extend the season … if you want the best product on the floor. We need proper time to rest and recover.”

The Indiana Fever won two of five games over an eight-day stretch that ended with a 94-86 victory over the Dallas Wings on Friday in Dallas. Ms. Clark missed her second straight game with a groin injury and remains questionable for the Fever’s match-up with the defending champion Minnesota Lynx in the second-ever WNBA Commissioner’s Cup Championship.

The game doesn’t count in the regular-season standings, but the winning team receives $500,000 to split among its players. “I’m doing everything I can to put myself in position to play the next game,” Ms. Clark told reporters. “That’s always my goal, to be available for the next game. I feel good. I’m just going day by day.”

Ms. Clark missed five games earlier this season with a quad injury, and aside from scoring 32 points in her return against the Liberty, she has since struggled with her shooting.

With Ms. Clark on the sidelines, Ms. Bueckers had a brilliant game against the Fever on Friday despite the loss, scoring 27 points. But she missed Saturday’s second game of a back-to-back with soreness in her right knee. It was the fifth game that the overall no. 1 pick from UConn has missed this season. She sat out three games with a concussion and another due to illness.

The Wings don’t play again until Thursday. Considering that Ms. Bueckers competed in a full collegiate season, leading the Huskies to the national championship, and joined the WNBA a month later, her body has had little time to rest and recover. Recovery guidelines will likely be part of a new collective bargaining agreement being negotiated between the players’ union and owners.

“I think player safety and player health is the main concern and making sure that is in the forefront and most important,” Ms. Bueckers said in Dallas. “It’s tough trying to fit 44 games into a compact schedule, but everybody is dealing with it.”

It’s assumed that expanding the season will come with the addition of more teams. Toronto and Portland were previously announced to be entering the league next year. Cleveland debuts in 2028, Detroit in 2029, and Philadelphia in 2030.

The ownership groups of the three new teams paid a $250 million expansion fee, about five times more than Golden State paid to enter the league this season. St. Louis, Kansas City, Austin, Nashville, Miami, Denver, Charlotte, and Houston also bid for expansion teams.

“This historic expansion is a powerful reflection of our league’s extraordinary momentum, the depth of talent across the game, and the surging demand for investment in women’s professional basketball,” Ms. Engelbert said.

Detroit and Cleveland will play at the existing NBA arenas in those cities, while Philadelphia will build a new venue to be completed in five years.

While Ms. Clark recovers from her injury, she can begin plotting her roster for the upcoming WNBA All-Star game on July 19 in Indianapolis. Ms. Clark, whose exclusive player edition shoe with Nike sold out in minutes on Monday, was selected along with Lynx star Napheesa Collier as captains for this year’s mid-season showcase.

The two were named captains after receiving the most fan votes. Ms. Clark received 1.2 million votes while Ms. Collier received 1.1 million. The captains will draft their respective rosters from the eight remaining starters selected for the game and then from the 12 reserves.

“It’s cool fans get to be part of it and have an impact on the game,” Ms. Clark said. “It’s going to be great to do it in this city.”