McLaughlin-Levrone, the 23-year-old world record-holder in the 400-meter hurdles who won the U.S. championship in the open 400 earlier this month in 48.74 seconds, was set to race the 400 meters on Friday in Monaco at a meet on the Diamond League circuit against a field including Lieke Klaver, Rhasidat Adeleke and Natalia Kaczmarek, all of whom have also run under 50 seconds this season.

Kersee, whose Los Angeles-based Formula Kersee training group includes McLaughlin-Levrone, termed the knee pain that led her to withdraw “nothing serious” but said she wouldn’t run out of caution given that less than one month remains before the world championships open in Budapest, Hungary.

As the reigning world champion in the 400-meter hurdles McLaughlin-Levrone owned a bye into the world championship in that event, but earlier this month she and Kersee chose to contest the 400 meters at these championships instead, citing what Kersee called at the time the “challenge” of vying for a world title in a new event. She has already run the 10th-fastest time in history. The hurdles remain part of McLaughlin-Levrone’s future, Kersee added.