FIFA's ruling council meets on Friday in Miami to discuss president Gianni Infantino's plans for an expanded Club World Cup and a new global Nations League tournament.
Also on the agenda is the potential expansion of the 2022 World Cup in Qatar from 32 teams to 48, with the possible addition of extra host nations for the tournament.
"Competition reforms are a natural and necessary part of innovation in sport. However, various reforms over the last years by different competition organisers have led to a crowded match calendar at the top of the game which, according to FIFPro research, is having an impact on the heath and performance of players," the union said in a statement.
"Therefore, any further amendments to international tournaments should only be introduced after a comprehensive review of the match calendar has been undertaken and mandatory standards for the rest and recovery of players have been introduced," FIFPro added.
FIFPro said it wanted to see compulsory mid-season and off-season breaks, and a limiting of matches and international travel each season.
The union also said that at international competitions such as the World Cup, the minimum rest period between matches of 72 hours must be maintained and not reduced to fit a tighter schedule.
FIFPro also argued that increased revenue from new tournaments and the expansion of existing competitions should be used to help players who are struggling in the game and address what it called "minimal investment" in the women's game.
Infantino has proposed the creation of a new 24-team Club World Cup, held every four years, and a global version of UEFA’s Nations League. He wants the tournaments to start in 2021.
The FIFA President said his plans, first put forward at a FIFA meeting in Bogota over a year ago, were based on an offer from an investment consortium willing to put in $25 billion over a 12-year cycle in return for 49 percent ownership of the competitions.
FIFA suggested earlier this month that other bids would also be invited once it had decided on the competition format.
(Reporting by Simon Evans; Editing by Toby Davis)
