Speaking to a media roundtable in the Qatari capital before the opening match of the Asian Cup, he said: "I expect it will be held in the winter.
"We have time to look at this question, it is still 11 years away but we must decide the most adequate period for a successful World Cup which means January or the end of the year."
Qatar was awarded the finals last month despite a report from FIFA's own inspectors that said playing matches in the summer when temperatures soar to more than 40 degrees Celsius posed a health risk to players and fans alike.
Since Qatar was chosen there has been a groundswell of opinion that the tournament should be staged in winter.
Blatter said that even though Qatar's bid document made no reference to switching from the traditional June and July period - and would instead use air-conditioned stadiums to counter the heat -- FIFA were not bending the rules.
"Do not forget there are still 11 years to go and although we have the basic conditions of their bid for a June and July World Cup, the FIFA executive committee is entitled to change anything that was in the bid," he said.
"We haven't broken the rules but when you play football you have to protect the main people, the players. There were already rumours about a winter World Cup even before, we even spoke about it in the executive committee."
Any switch to winter may take years to be agreed as it would clash with many of the domestic leagues, particularly the powerhouse European ones.
The Qatari FA has yet to establish its organising committee for the finals and, technically, it will be up to that committee to submit to FIFA a request to change the dates.
However, a switch could yet be prompted by FIFA itself.
Any move to winter could have a massive impact on other global sports with major events like the Winter Olympics and the Australian Open affected.
SPOKE OPENLY
Blatter rebuffed suggestions that there was any corruption at FIFA, insisting it was totally transparent in all its dealings. If that was the case, he was asked, how was it that Qatar was awarded the finals when FIFA's own inspection team criticised its bid and said it posed a health risk.
"You can have the best report and the worst report but finally it's human beings that make the decision," he said.
He also repeated his pledge to continue taking the World Cup to new territories, citing India as a possible future host.
"Back in the 1980s when we started this process under Joao Havelange, it was always a wish to make football universal," he said. "We have been to Africa and again it was time to go to new territories. It was all a strategy within the double decision for 2018 and 2022. It's a logical move."
Australia had bid against Qatar and Blatter admitted he had no idea why their bid only received one vote last month.
"I know they were shocked, bitterly disappointed, but I dont know why it happened," he said.
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