The 2024 Copa América started on June 20 with what should've been only a celebratory occasion. In front of 70,524 fans at Atlanta's Mercedes-Benz Stadium, reigning FIFA World Cup champions Argentina triumphed 2-0 over Canada in a perhaps surprisingly competitive game. But talk of the result faded into the background after the players voiced frustration and anger over the conditions of the field provided by CONMEBOL.

With the 2026 World Cup set to be played in many of the same venues across the United States, each new controversy over pitch conditions at Copa América accentuates the ongoing concerns about the quality of the venues and the difficulty of using NFL stadiums for soccer. At Copa América, some stadiums are natural grass, but several have artificial turf, in which layers of temporary grass have been laid over the field.

So why did CONMEBOL opt for these field specifications, and will conditions improve when the U.S. co-hosts the world's biggest sporting event with Canada and Mexico in two years' time?

Argentina boss Lionel Scaloni led the charge after the final whistle last month, questioning why the South American football confederation waited until 48 hours prior to the match to prepare the field.

"They knew seven months ago that we'd play here and they changed the field two days ago," he said angrily at the postmatch news conference. "It's not an excuse, but this isn't a good field. Sincerely, the field is not apt for these kinds of players. We gave not necessarily a good game, but a game according to the pitch and what the opponent proposed. We couldn't do much more with the conditions of the pitch. Look at the speed of the passes that we did."

Goalkeeper Emiliano Martínez added to the frustration: "Very bumpy. We faced a strong Canada side on a pitch that was a disaster. It jumped on you as you ran. We must improve in this aspect -- otherwise, Copa América will always appear at a lower level than the European Championship."

It wasn't just Argentina players who haven taken issue with the fields during Copa América. United States midfielder Weston McKennie said after playing at Mercedes-Benz Stadium: "I think what Martínez was saying was completely true. You're playing on a football field, with laid grass that's all patchy and it breaks up every step you take. It's frustrating,"

Peru manager Jorge Fossati cited AT&T Stadium's unsatisfactory field as a potential reason for the Achilles injury of Luis Advíncula: "It came out of nowhere. I realize that this is a grass field today but it's not normal grass. It's not grass that's born, and grows [naturally]. It's a grass they bring in from elsewhere. That can be a bit of a harder surface and it can affect you in that exact place [the Achilles]. I'm not a doctor but I've been around football for a few years."

Brazil superstar Vinícius Júnior, Canada's Kamal Miller, Colombia's James Rodríguez and Chile manager Ricardo Gareca stand among the many prominent figures who have all also voiced their concerns over the field conditions.

CONMEBOL announced the 14 stadiums selected to serve as venues of Copa América matches back in December. A combination of NFL, MLS and multi-purpose stadiums were chosen, with six venues utilizing artificial turf and eight stadiums a field of grass. Three Major League Soccer venues made the cut: Austin FC's Q2 stadium, Sporting Kansas City's Children's Mercy Park and Orlando City's Inter&Co stadium.

Frederico Nantes, CONMEBOL's director of competitions, said the size and maximum capacity of soccer-specific MLS venues played a role in the choice to limit their use throughout the tournament. Matters of size, travel distance between cities and infrastructure were taken into consideration before CONMEBOL understood that artificial turf could not be avoided despite outcries from players regarding that playing surface.

To achieve uniformity and fairness, CONMEBOL opted to standardize field conditions by ruling each stadium required adjustments to be made in order to comply with the need of a 100m x 64m pitch (a traditional field measures at 105m x 68m) and grass field with 25mm density. Copa América participants were informed of the dimension change eight months prior to the tournament, once again raising concerns.

Though host venues were confirmed in December, preparations at each stadium began seven months prior to the announcement to accommodate the newly implemented rules. CONMEBOL held conversations regarding pitch maintenance, stadium management, logistics and coordination in June 2023 to be prepared for the competition.

"We started the project in June, when traveling to analyze fields and watch games here, and in November, we began inspections in all stadiums and all training centers," Maristela Kuhn, CONMEBOL's agricultural engineer, said. "Reports were generated with recommendations of everything that had to be done. We had meetings with the agronomists and programming. With a special technology, we had all the grass plantations defined."

The grass produced across the United States for the tournament utilizes a special technology, whereby the company seeds any material on top of a bed of plastic to ensure all grass grows to an unwavering height and density. CONMEBOL labeled the system "ready to play," due to the product's ability to be transported, installed and available for immediate use. Kuhn confirmed the technology was the same used on pitches in Europe, indirectly responding to those comments comparing the Copa América and European Championship conditions.

Despite the promise of consistency in standards of measurements and quality across fields, each stadium received different treatment once the competition began due to weather and construction conditions.

For the inaugural match at Mercedes-Benz Stadium, pitch installation started three days prior to the game on June 17 when a refrigerated truck transported the rolls of grass to the stadium for stadium crews to complete the 48-hour conversion. The panels of grass were laid on top of the artificial turf individually to create the necessary cross-sections, before the CONMEBOL crew began the aesthetic work of outlining the pitch.

The federation completed several tests prior to the game, including resistance and performance trials, to ensure the grass met the organization's standards of quality, density and force. But the measures failed to convince participants, insisting the panels of grass parched together affected the speed of play and the way the ball rolled.

"They sewed panels of grass together. It's painted to appear nicer than it is," Scaloni observed.

Two weeks after the initial match, CONMEBOL reassured media that the pitch was worthy enough to host world-class players for the competition. The federation ran a second round of tests on the field before the U.S. men's national team's match against Panama, and found no reason to replace the grass or re-install panels.

"The grass in Atlanta posed absolutely no threat. All the tests came out sufficient," said Nantes. "I think the aesthetic of the field was what posed a problem for the players, they care a lot about aesthetics."

Kuhn added: "In Atlanta we had the option of doing a second conversion, it is a closed stadium, ready for conversion and we decided not to change because the grass was very good and based on technical evaluations we decided that it would not be necessary to change and we kept the first grass until the second game."

Venues with year-round grass, like Hard Rock Stadium, GEHA Field at Arrowhead Stadium, and Levi's Stadium, underwent a much less rigorous process. The fields were still replaced with new, CONMEBOL-approved grass but placed two weeks ahead of the first match. Hard Rock Stadium, however, will see a second field change four days ahead of the final on July 14.

Despite the timeframe of installation and previously laid surface, CONMEBOL confirmed height, density and temperature checks, and resistance testing were done before and after completion in every stadium to enforce uniformity. Though the grass was grown to fit certain measures and standards, the variance in installation process and surface base provided teams with a different playing experience. The density, height, and force of the grass didn't pose a harsh discrepancy, but the base surface in which it was laid on top of did.

The difference in surface areas from venues with artificial turf like that of Mercedes-Benz Stadium, AT&T Stadium and MetLife Stadium provide varying conditions from those that boast year-round grass like fields in Miami and Kansas City.

Eight of the 14 venues used for Copa América will also serve as hosts for the 2026 World Cup, and those with artificial turf will return. But FIFA is set to implement a different set of rules when bringing the international tournament to North America to avoid any disparity in experiences. Under FIFA regulations, eight of the 16 stadiums planned to host World Cup matches that typically employ artificial turf fields will be required to install temporary natural grass surfaces for the tournament. But according to Alan Ferguson, FIFA's chief field czar, all fields will be of the hybrid variety, where a minor percentage of artificial fibers are woven into natural grass to create a sturdier surface.

FIFA's goal, like that of CONMEBOL for the 2024 Copa América, is to create 16 fields that look, feel and play almost identically, regardless of climate, type of grass and stadium infrastructure.

"It's important that we get these pitches playing and look as identical as we can," said Ferguson. "Whether it's a stadium in Canada, in the Midwest U.S., or down in the mountains of Mexico, we want there to be consistency with what a player feels under his foot. For us, it's all about the consistency of the playability for the player."

The tournament will employ 16 host stadiums, 84 training sites and 178 practice fields, making uniformity complicated the way it has been throughout the Copa América. The challenges prompted FIFA to implement a research and development project to produce the perfect pitches for the tournament after announcing the host cities in June 2022. FIFA intends to tackle the problem of uniformity differently than CONMEBOL, giving participating countries hope that a solution may be found ahead of the 48-team international competition in two years.