The tournament in Qatar last year was held in the winter for the first time due to the climate in the Middle Eastern country but Fifpro has said that the event must be arranged differently to place fewer demands on the players.
The union's general secretary Jonas Baer-Hoffman explained that a winter World Cup "should not be a viable option for anybody" and that major changes would need to be made to the European club schedule if it did happen again.
Baer-Hoffman said: "Repeating what we had this time is clearly not acceptable.
"If you want to pursue a winter World Cup again, you need to get into conversations with the leagues to completely change their schedules to provide appropriate training and recovery time.
"That would mean a two or two-and-a-half month break from competition. I find it unlikely they would agree to that."
FIFA president Gianni Infantino previously praised the decision to play in the winter and believes that Qatar was the "best ever" tournament in the competition's history.
He said at the end of the tournament last year: "Football [has] reinforced its unique cohesive power by uniting the world in a spirit of peace and friendship.
"For me the World Cup has been a real incredible success on all fronts. The main one... bringing people together, meeting the Arab world, is very important for the future of all of us. But also when it comes to the matches. It has been the best World Cup ever.
"Playing in November and December has had an impact. We have seen it with the quality of the games."