The NFL’s first game in Rio de Janeiro is still scheduled for Sunday, but the condition of the field at Maracanã Stadium has drawn a sharp response from NFL Players Association executive director JC Tretter. With the Baltimore Ravens and Dallas Cowboys set to play there, Tretter said the league’s international ambitions must come with playing surfaces that meet its standards.

In a statement addressing the field, Tretter said the concern heading into the game was that loose, patchy grass could cause players to slip. He distinguished that problem from a surface that poses a significant injury risk, but argued that playability matters too. Players should be able to cut, change direction, and perform at the level expected in an NFL game without worrying about whether the ground will hold beneath them.

“Players can overcome a lot. But they shouldn’t have to overcome the field,” Tretter said, in what was a rather long statement.

According to Tretter, NFLPA and league field experts have spent days in Brazil monitoring the surface. The union’s experts recommended reinforced stitching to improve traction and help the grass stay together, and equipment was brought in to treat as much of the field as possible before kickoff. Tretter said those evaluations would continue through Sunday.

The concern did not emerge in a vacuum. Local soccer players had already criticized the condition of Maracanã’s grass, prompting questions about whether it would be ready for football. Earlier this week, NFL field director Nick Pappas expressed confidence in the preparations, and there was no plan to move the game.

Tretter also pointed to a broader issue: By the union’s count, two of the NFL’s three games in Brazil will have faced field-related concerns. This weekend’s matchup is the first in Rio after the league’s previous Brazil games were held in São Paulo. In his view, the latest scramble to improve the surface shows why the NFL needs standards that cover performance as well as safety.

The union is not arguing that the Ravens and Cowboys cannot put on a good game. Tretter’s criticism is aimed at the decisions made before players take the field. As the NFL continues expanding internationally, he wants the league to show it can meet the same playing standard abroad that it expects every week at home.