The Women’s World Cup in Canada is less than 10 months away, and the last thing FIFA wants on its hands is a lawsuit from the top players in global women’s soccer. But that’s exactly what those players are threatening publicly right now if FIFA and Canadian organizers don’t change their plans to stage the World Cup on artificial turf fields in the tournament’s six stadiums.

The U.S.’s Abby Wambach, Alex Morgan and Heather O’Reilly are some of the players whose legal representation—which includes a Canadian firm and the same U.S. firm that brought the recent O’Bannon vs. NCAA case—sent a letter to FIFA and Canada 2015 organizers in late July threatening a lawsuit. As of Monday, FIFA and the Canadians had acknowledged receiving the letter but had yet to respond.

The Americans are hardly the only players ready to take FIFA to court for what they view as a case of gender discrimination, considering the men’s World Cup has never been played on artificial turf and won’t be in 2018 or ’22, either.

Current FIFA Women's World Player of the Year Nadine Angerer, the German national team goalkeeper, told SI.com she’ll do whatever she can to ensure the World Cup is played on natural grass, just like every previous senior Women’s World Cup.

“From the perspective of goalkeepers, we have to jump on this concrete,” Angerer said. “We are landing all the time, and it’s really bad. I played just a few weeks ago in Vancouver on this turf [in a Germany-Canada friendly], and it’s really embarrassing. Seriously, it’s concrete.”

The Women’s World Cup final is set to take place on that turf in Vancouver at B.C. Place next July 5. And while Canadian organizers promised in their proposal that each stadium would have the highest-rated artificial surface—known as FIFA-recommended 2-star turf—let’s just say Angerer’s description of the Vancouver field didn’t fit the two-star rating that it already has.

Angerer had another question as well: “I can’t understand why the women have to play a World Cup on [artificial] turf. Why just for the women and not for the men?”

Spanish star Vero Boquete, who plays alongside Angerer and Morgan for the NWSL’s Portland Thorns, told SI.com that Brazil star and five-time Women's World Player of the Year Marta has joined the group that could file a lawsuit against FIFA.

“[Marta] is with us totally,” Boquete said. “I spoke with her recently, and she agreed with us.

“We play on turf [in Portland], and we know how difficult it is to recover when you play on turf,” Boquete continued. “In the World Cup we have to play in a short time many games. It’s not the same recovery, and that will mean the level is worse off and won’t be the best that it can be.”

For Morgan, there are other issues, too.

“Two main reasons stick out to me,” Morgan said. “The first is that many of the injuries I’ve had in the past have come from artificial turf. Injury prevention is a big thing for me. The second thing is the game is played differently. The bounce on the surface is different, and a lot of players don’t play the same way on turf as on grass, because they don’t want to go down for a slide tackle or do a diving header.”

Canadian World Cup organizers referred all requests to FIFA, and while FIFA confirmed the receipt of the players’ letter to SI.com, a spokesperson added the organization would have no further comment at this time.

Staging tournaments on approved artificial turf surfaces is within the rules of FIFA, and senior men’s World Cup qualifiers as well as games in the men’s and women’s Under-20 World Cups have taken place on the fake stuff. Proponents of Canada’s successful bid to host the 2015 tournament note that artificial turf surfaces are better suited to year-round use in the cold Canadian climate. The use of artificial turf was part of Canada’s original bid, for which the only competition was a bid from Zimbabwe (which eventually pulled out).

A few questions remain about the situation:

• If the NWSL has six artificial turf fields in its league, why haven’t the players considered a lawsuit over that?

For Morgan, the World Cup is the quadrennial showpiece event of her sport and shouldn’t be subject to the compromises that come with trying to make a women’s soccer league work after two other leagues folded in the last 11 years.

“For me the obvious reason is there’s lots of planning involved in the host nation [of a World Cup],” Morgan said. “In Brazil, they had to spend millions of dollars and years of planning to put these venues around the country for the men’s World Cup. All we’re asking for is a good surface to play on. This is a tournament that comes around once every four years and is the pinnacle of football. Although we’d like to play on grass day in and day out, we’re not always given that option with our NWSL teams. But with the amount of planning that goes into the host nations for the male and female World Cups, we should be given the best surface to play on.”

• Is there even enough time to have good grass surfaces installed in the Canadian venues?

The players’ legal representation thinks so.

“We’ve spent a lot of time talking to grass experts, and there’s no question that there’s plenty of time at this point,” said Hampton Dellinger, one of the players’ attorneys at Boies, Schiller and Flexner. He cited the successful grass tray system used at the Pontiac Silverdome during the 1994 World Cup, as well as the rolling system at University of Phoenix Stadium in Arizona and the temporary grass used at the Rose Bowl national title college football game last year.

• What sort of gender-discrimination legal argument might the players pursue?

Dellinger said his team is looking at a number of laws, but they’re focusing right now on the Canadian human rights codes in each province and the national Canadian charter on rights and freedoms.

“All of them say you can’t discriminate on a lot of things, including facilities and accommodations,” Dellinger said. “I think it falls squarely into those provisions.”

Dellinger’s team noted that a Canadian soccer executive, Shannon Pederson, a member of the board of directors of the British Columbia Soccer Association, recently admitted while criticizing the lawsuit threat: “That said, would FIFA ever consider the use of artificial turf in the men’s tournament? Most likely not.”

Regardless of whether the players’ threat escalates into a lawsuit, it’s not a good look for FIFA to have the best players in women’s soccer talking about taking legal action against the organization. And while the players say they won’t boycott the World Cup if their appeals are denied, they’re preparing for a potential battle in the courtroom.

“We have a lot of support from many countries," said Morgan, who argued that FIFA (with its $2 billion in profits from this year’s men’s World Cup) can easily afford to make the playing surface changes. "We’re talking about Spain, Germany, Brazil, England, Mexico, New Zealand and the list goes on. We want people to agree with our standpoint and accept the fact that the tournament should be played on a grass surface. We’re hoping not to go to court, but if they don’t respond and if nothing is done to change the situation with the host nation and the venues, then we’ll have to move forward eventually.”

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