FIFA's executive committee will next month discuss shifting the finals to the winter because of the searing heat in Qatar in the European summer.
The European Professional Football Leagues (EPFL), mindful of the impact on their competitions, said FIFA should consult widely before making any change to the regular schedule of playing the World Cup in June and July.
"Such an important decision cannot be rushed with artificial deadlines," the EPFL said in a statement.
The Swiss-based EPFL represents leagues from across the continent including the big five of Germany, England, Spain, Italy and France.
As well as disrupting club competitions, the EPFL said a date change would have an impact on player contracts and the transfer system which is based on a European season running from August to May.
It also noted a potentially damaging clash with the 2022 Winter Olympics, another major attraction for sponsors and broadcasters.
The EPFL called for a medical assessment of the impact of a summer World Cup on the health of players and fans before any decision was made.
Premier League chief executive Richard Scudamore has argued that a winter World Cup could disrupt the European calendar for up to three seasons because of the knock-on effects of having to stop and start a campaign.
However, the momentum towards playing in Qatar in the winter seems hard to resist.
FIFA president Sepp Blatter has already backed a switch to the winter and conceded on Monday that it may have been a mistake to award the tournament to the tiny Gulf state.