A Moment of Truth for American Grass

Every time the United States hosts a major international soccer tournament, the world’s finest players unite to complain about our god-awful fields. At the 2024 Copa América, the Argentine goalkeeper Emi Martínez—widely regarded as one of the best in the world—described the field in Atlanta’s Mercedes-Benz Stadium as both “a trampoline” and “a disaster.” Last year, Chelsea’s captain, Reece James, who played a Club World Cup match in New Jersey’s Met Life Stadium, called the pitch bad for the joints and the quality of gameplay. This year, MetLife Stadium will host the single biggest match in soccer: the World Cup final.The United States’ poor record on grass has prompted fans and soccer analysts alike to speculate that turf will be the villain of this year’s tournament. FIFA doesn’t allow professional games it hosts to be played on fully synthetic surfaces, but the United States’ largest stadiums are mostly designed with artificial turf for NFL games. So, shortly after Canada, Mexico, and the U.S. won their joint bid to host the 2026 World Cup, FIFA began approaching grass researchers, who have since received millions of dollars to figure out how to turn American football stadiums into, well, football stadiums. You might call this effort the World Cup of grass science.Slight differences in turf can make a major difference in elite play. Grass that’s even half a centimeter too long can generate unexpected friction that throws off the timing of passes. Grass cut too short can shift the game to a frantic pace. Last year, during a FIFA game held in Cincinnati, the strange physics of the turf contributed to a goal so absurd that analysts said it looked like “a glitch from a 2002 video game.” (A FIFA spokesperson told me in an email that the pitches for the 2026 World Cup represent a “significant evolution” over last year’s Club World Cup.) John Goff, who studies the physics of soccer at the University of Puget Sound, told me that if the ground is too hard, cleats can’t pen