NFL to use new device to check field conditions

The NFL and NFL Players Association have mandated the use of a new device to measure field conditions before regular-season games this season, league officials told ESPN.

The development and introduction of what is known as a “Strike” device is part of a larger effort to create a set of universal guidelines for the league’s 30 playing surfaces, all while addressing a contentious issue between owners and players in recent years. Those guidelines, NFL field director Nick Pappas said, are expected to be in place for the 2025 season.

“We’re going to come up with our own performance specification document for the NFL field,” Pappas said. “Ultimately it will be a regulatory document that says, ‘Hey, look, an NFL field should meet these standards.’ Right now, our standards have been somewhat vague, but it’s because we didn’t want to just arbitrarily adopt something that could be wrong.”

NFL players have long pushed the league to improve playing surfaces. In 2023, NFLPA executive director Lloyd Howell called on owners to convert the league’s 15 artificial turf surfaces to grass. The league has pointed to data that shows a relatively narrow gap of noncontact, lower-body extremity injuries on natural and artificial surfaces, and instead has argued that consistency across surfaces is a more realistic goal.

In addition to the Strike, the league will continue to use its Clegg device to measure field hardness before games. NFL rules require Clegg readings between 50g and 100g for a surface to be approved for play.

The Strike device, built through the league’s biomechanical partners, will provide different data that Pappas said will provide a better assessment of field conditions. It will deliver a metric based on two energy measurements. The first is restitution — how much energy is absorbed by the ground versus being sent back to a player when he steps on it. The second is deformation, the extent to which the surface dimples when it comes into contact with the foot.

Only the Clegg reading will be used for compliance during the 2024 season, but the Strike metrics will be incorporated into next season’s guidelines and likely will replace the Clegg in the near future.

“We believe that [the Strike] is more indicative of that initial puncturing of the surface of how a cleat penetrates the surface and displaces infill or displaces sand or root material,” Pappas said.

“That is what we believe is going to give us a more true value to what the player is feeling and a better way to measure our fields moving forward. The Clegg has done great things for us in the initial low-hanging fruit of getting us to an improved standardization, but there may be some diminishing values at this point on it where we need to take it a step further to better understand our fields.”