Southampton boss Mauricio Pochettino has slammed FIFA's international calendar.
Saints duo Gaston Ramirez and Maya Yoshida are battling to be fit for the new season.
They played in last month's Confederations Cup in Brazil and have only just returned to the Saints.
Pochettino said: "The FIFA schedule is inconvenient for every manager.
"We are angry because Gaston and Maya played in the Confederations Cup so came late and don't have the same fitness as the other players.
"We will try to get them ready for the first game but we do not know yet."