Mr Blatter told one news agency that an October 3-4 meeting in Zurich should approve the change, and begin consultation on the best time for Qatar to host the tournament.
Mr Blatter said he would be "more than surprised if the ExCo will not accept the principle you cannot play in summer in Qatar".
The Fifa head said agreeing new dates "would be then decided later".
Mr Blatter said this would involve consultations with leagues, clubs, national associations and players.
Qatar's suitability in June and July was questioned even before Fifa's board chose it in December 2010.
Qatari officials have said they will change plans if Fifa formally requested it.