NFL's international playbook calls for vigilance on field quality, from Sao Paulo to Bernabeu

LONDON (AP) — Nick Pappas rattles off the types of field surfaces at international stadiums the way a quarterback calls plays in the huddle.

Carpet hybrid ryegrass at Croke Park in Dublin. Stitched hybrid bluegrass at Olympiastadion in Berlin. Stitched hybrid ryegrass at Santiago Bernabeu in Madrid. Those three are the new host cities this season on the NFL’s busy international calendar.

As the NFL's field director, it’s Pappas’ job to make sure the international playing surfaces meet league standards. Expanding American football around the world presents some challenges.

“Our athletes are very unique in the fact that they’re bigger and stronger and faster than most athletes,” Pappas said.

And when the likes of 300-pound linemen plant their feet and smash into each other for thre