The 74-year-old Swiss president of world football's governing body, who apologised on Tuesday for the errors made by referees this week, has been a stubborn opponent of technology for years.
He effectively closed the door on further discussions about it three months ago at the annual meeting of football's law-making body, the International Football Association Board (IFAB).
Although he has again ruled out using video replays to help officials with decisions, such as offsides, he said technology such as the Hawk-Eye system used in tennis and cricket should be re-examined to determine if the ball had crossed the line or not for a goal.
"It is obvious that after the experiences so far at this World Cup it would be a nonsense not to reopen the file on goalline technology," Blatter said at a briefing with selected media on Tuesday.
He was referring specifically to the incident in Sunday's England-Germany match at Bloemfontein when a shot from England midfielder Frank Lampard struck the bar and bounced down well over the line when England, chasing a comeback, were 2-1 down.
The goal was not given and Germany went on to win the second round match 4-1.
Although there was a second controversial incident later in the day when Argentina scored from an offside position against Mexico in a match they won 3-1, Blatter emphasised no technology would be debated relating to video evidence for offsides.
He said: "We will look again at technology, goalline technology, at the business meeting of the International Football Association Board in Cardiff, Wales in July.
"The only principle we are going to bring back for discussion is goalline technology. For situations like the Mexico game you don't need technology."
OPEN MIND
Paul Hawkins, whose Hawk-Eye Innovations company of Winchester, England, developed the system, was keeping an open mind about Blatter's comments.
Hawkins told Reuters: "Mr Blatter has said this before and there have been other changes of mind. All he said is that they will reopen the discussion, they haven't said they will change their minds.
"If they're serious about this then they'll contact us and we'll just wait to find out whether this is just a little statement to defuse the current public pressure.
"I have had my hopes dashed too many times in the past to get too excited, but obviously we think we can help make football a better game."
Only hours after Blatter spoke, World Cup referees said they would welcome technology if it made their jobs easier and helped the decision-making process.
"I am open-minded for anything that would make us more credible," referee Howard Webb told reporters after a World Cup referees' training session in Pretoria.
"Whatever tools I have I will use to the best of my abilities."
Blatter said that while FIFA would reconsider the goalline technology debate, he was not sure the Hawk-Eye system was 100 percent accurate.
