BETHESDA, Md. >> The union for Major League Soccer players criticized FIFA, its rules-making body and the league for failing to allow trials of temporary substitutes to replace players suspected of sustaining concussions.

The International Football Association Board said Jan. 18 that no consensus was reached on the proposal for trials by MLS and England’s Premier League. The IFAB includes four representatives from FIFA and one each from the governing bodies of England, Scotland, Wales and Northern Ireland.

The MLS Players Association said in a statement on Friday that current rules “do not provide sufficient time for the proper assessment of players for potential concussions.”

“Players too often remain in games with head injuries,” the MLSPA said. “Medical professionals also agree that the solution to this problem is to provide for temporary concussion substitutes to allow players to be properly evaluated.”

MLS starts its season today, and the union said the league should have adopted a trial without the IFAB’s approval.