The Professional Footballers Association reiterates that it is "taking legal action" against FIFA following the fixture congestion that is affecting the players.
Manchester City midfielder Rodri said on Tuesday that players are "close" to going on strike because of concerns over the increased workload.
Rodri already played 63 games for club and country last season and faces the prospect of an even busier schedule because of the expanded Champions League and the revamped Club World Cup.
"As unions, we are already taking legal action to challenge this and players are now openly talking about what options are available to them to force change," PFA president Maheta Molango said in a statement to ESPN on Wednesday.
"They want to be listened to, and those who run the game must now sit up and take notice."
Molango believes the issue must be addressed now.
"The impact of fixture congestion and increasing player workload is no longer a problem that's coming down the line," she said. "It's already here. This is the year when we can look at the calendar and say clearly 'this doesn't work.'
"Players see that, and they are now experiencing it. They're making their feelings increasingly clear but, as I've said before, this is no longer just a player problem -- this is a problem for everyone in football."
Top international players competing in the Champions League and Club World Cup could end up playing as many as 85 games this season.
Real Madrid coach Carlo Ancelotti already expressed his concern over the hectic schedule earlier this week.
"If those who rule football, who make the decisions, don't come to the conclusion that the players get so many injuries because they play too much, then we do have a problem," he said. "What I ask is to start thinking about reducing the number of games in order to have more attractive competitions."
David Aganzo, president of the Spanish Players' Union (AFE), is backing the players to go on strike if there is "no other choice."
"Rodri is an important player in Spain and England," Aganzo told Diario As. "He is thinking about the footballers. I am on his side. His words are very clear. If we have no other choice, we will have to go on strike. We have tried to do everything possible to dialogue with FIFA and UEFA.
"UEFA has completely changed the calendar and they have put in more matches and nobody has said anything. Surprising."
AFE said in a statement on Wednesday: "The health of footballers should be a priority and is not negotiable. The situation has reached a limit that cannot be allowed to continue."
Manchester City star Erling Haaland said earlier this summer that the increasing number of games takes a toll on the players.
"I think we all saw in the Euros in general how tired people were," he said. "You could see the level, you could see even in people's faces how tired they were of football, if you can say it that way...It's difficult to be sharp if you play over 70 games a year."
LaLiga president Javier Tebas said action must be taken.
"It is time to say enough is enough," Tebas said on Wednesday during the 2024 World Football Summit.
"The arrival of the [revamped] Club World Cup [which will start in June 2025] has burdened the calendar even more. Now we are only talking about four more Champions League matches ... I support the strike that Rodrigo is talking about because it is not only a health problem for those 70 players but also a problem for the balance of the industry.
"In the end, what FIFA is looking for, above all, is that the [domestic] leagues that have 20 clubs reduce their competitions. And we are not going to accept that. Reducing a national league has a cascading effect, like reducing the other divisions. Everyone thinks that for the industry to grow, more competitions with more matches must be held ..."