Some of the biggest names in the game won’t be playing in the Women’s World Cup because of what feels like an epidemic of ACL injuries — and players are asking why.

Netherlands forward Vivianne Miedema, England’s Leah Williamson and Beth Mead, Canada’s Janine Beckie and rising U.S. star Catarina Macario are among those sidelined for the tournament starting July 20 in Australia and New Zealand.

“I think it’s a multifaceted issue. I don’t know if I’m the expert in it, even though I’ve experienced it,” said U.S. midfielder Andi Sullivan, who tore her ACL in college at Stanford.

“There’s so many different factors that could contribute to that and I think we are a little bit behind on the research as to why, so hopefully now the prevalence will kind of wake people up,” Sullivan added. “This is an issue we need to pay attention to and look more into preventing and how to handle it better.”

Last year it was estimated that nearly 60 players in the world’s top professional women’s leagues were sidelined because of anterior cruciate ligament injuries. Among them was Spain’s Alexia Putellas, who injured her ACL just before the Euros last July.

Putellas, who will play for Spain at the World Cup, partnered with FIFPRO, the international players’ union, to call attention to the outbreak of ACL injuries and demand a closer look at possible contributing factors including workload, medical care, field conditions and even equity.

Studies have shown women are up to eight times more likely to suffer ACL injuries in sports involving sudden changes of direction, like soccer and basketball, than their male counterparts. Dr. Mark Cullen, the team physician for the University of New Hampshire who specializes in orthopedic surgery, says women have wider hips which impacts knee mechanics.

“They also tend to land a little bit more stiff-legged and don’t absorb the forces as well as their male counterparts, and that puts more force on the ACL and contributes to the tears,” Cullen said.

Katie Rood, who plays professionally in Scotland, was hoping to make New Zealand’s roster and play in soccer’s biggest tournament on home soil. But she recently announced that she had joined the “ever-growing ACL club.”

“It’s been an interesting process so far and one I’m sure I’ll learn a lot from, especially as it’s a serious issue in the women’s game. What’s hit me quite hard in this situation is just how many times I’ve been asked ‘Is the club looking after you?’” she wrote. “It’s a reminder that health care and medical treatment isn’t often the norm in the women’s game and we all know of players being left to fend for themselves after getting seriously injured with their clubs.”

Rood, however, praised her team for their support.

Miedema won’t be ready in time to help the Netherlands when it returns to the Women’s World Cup after finishing as runner-up to the United States four years ago in France. She is one of four players from Arsenal in the Women’s Super League currently sidelined by ACL injuries. The list includes Williamson, who tore her ACL in April.

When Arsenal’s Laura Wienroither tore her ACL earlier this month, Miedema posted on social media: “At least we will all be in the gym together. PS. ACL group is full now. Please no more.”

Five of the nominees the 2022 women’s Ballon d’Or — Putellas, Miedema, Macario, Mead and France’s Marie-Antoinette Katoto — all sustained ACL injuries last year.

Mead, who won the Golden Boot at the Women’s Euros last year, was left off England’s 23-player roster for the World Cup.

“We have to take care of players and do what’s smart, and not do what’s a little bit naive,” England coach Sarina Wiegman said.

Having already lost Katoto, France was dealt another ACL blow when Delphine Cascarino tore her ACL while playing for Lyon.

Lyon teammate Macario, one of the most promising young U.S. attackers, tore her ACL last June. Macario rehabbed at Aspetar, a specialized sports medicine facility in Qatar, but announced in May that she wouldn’t make it back in time for the World Cup.

Aside from the mechanics, there’s an emotional toll that such long-term injuries take on athletes. For some, it means the loss of a paycheck, for others it may be that their careers stall or are cut short.

Others miss out on chances to play in the World Cup.

Tierna Davidson, who plays for the Chicago Red Stars in the National Women’s Soccer League, tore her ACL last March. She said the injury and the rehab helped her appreciate her career.

“At the beginning, I felt like I was impatient and I was frustrated. When is this going to be over?” Davidson said. “But I think throughout the process, I really learned how to be patient and how to listen to myself and allow myself the space to enjoy the good things, which is important when you’re going through something like that.”