Blatter also said he wanted only professional referees to officiate at the 2014 World Cup in Brazil and admitted that women's football was struggling to progress.
Last year's World Cup in South Africa came at the end of a long season and a number of leading players performed below their expected level including Wayne Rooney, Cristiano Ronaldo, Kaka, Lionel Messi and Fernando Torres.
"In my view, and this is something on which (UEFA president) Michel Platini agrees, domestic championships are too long because there are too many teams and too many matches," Blatter said in an interview on FIFA's website on Wednesday.
"Teams in leagues with 20 clubs play 38 games, on top of which they also have national cup competitions and league cups, etc.
"This also creates a conflict of interest between national teams and clubs, some of whom complain that their players come back tired or injured. That's not the fault of the international calendar, however, and it's a subject that ought to be discussed."
Blatter's comments conflicted directly with the view of European Clubs' Association president Karl-Heinz Rummenigge, who criticised the international friendlies played at the start of this season.
Rummenigge said in September that clubs wanted a greater say in the international calendar and described the August matches, which included Spain flying off to Mexico only one month after winning the World Cup, as "nonsense" games.
NOT ENOUGH
Blatter said he wanted only professional referees officiating at the 2014 World Cup.
"That's a target we have to reach. Coaches are professional now and so are players, and there's no reason why referees shouldn't be either," he said.
"Some people say there's not enough money to pay them, but there always seems to be plenty in the professional leagues.
Blatter said he hoped this year's women's World Cup in Germany could spark interest in the sport.
"I think it's important it's taking place in the heart of Europe, in a country where women's football is strong," he said.
"The women's game has struggled to gain acceptance in financial terms. People don't seem to have much faith in it, but Germany can change that by putting on a good tournament and, more importantly than anything, filling the stadiums. A crowd of 50,000 is expected for the opening match in Berlin, which is already a great achievement.
"Young women have a lot of passion for the game. It's a sport anyone can play, but when women reach a certain age or level they find there aren't any professional leagues around, which makes it difficult for them to carry on playing. Technically, however, the game has improved a great deal."
