Mallory Swanson tore her patella tendon in Saturday's friendly against Ireland, the U.S. women's national team confirmed on Sunday.
Alyssa Thompson will replace her on the team training camp roster ahead of Tuesday's rematch.
Swanson went down late in the first half of Saturday's friendly in Austin, Texas. Visibly in pain, she was carted off and eventually taken to the hospital for further treatment. The U.S. pulled out a 2-0 win but at the cost of its leading goalscorer.
The injury is devastating to Swanson, the Chicago Red Stars and the USWNT's momentum heading into the World Cup in July. Recovery time for a patella tendon is at least six months, with many athletes requiring closer to a year before returning to full strength.
The 24-year-old has been unstoppable for the national team this past year. She's accounted for seven of the team's 16 goals in 2023, while no other teammate has scored more than twice.
She's been similarly dominant in club play, finishing this past season in the top-five for both goals and assists with 11 and six, respectively. With the 2023 season only two weeks underway, the Chicago Red Stars will miss Swanson's offense presumably for the entirety of the season.
Taking Swanson's place at the training camp is Thompson, the No. 1 pick in the recent NWSL draft. She was first called up to the senior squad in September at the age of 17, making her the youngest national team member since Sophia Smith in 2017.
Since going pro, Thompson has appeared in two league games for Angel City FC and recorded one goal.
The U.S. women's national will head to St. Louis for a rematch against Ireland on Tuesday. This will be their final friendly of the year before opening World Cup group play against Vietnam in New Zealand on July 21.