The Azzurri captain, a key member of the triumphant side of 2006, will be replaced by PSG goalkeeper Salvatore Sirigu at the Arena Amazonia in Manaus.
And Buffon raised fears he could miss more than Italy's opening match with a social network post that suggested his tournament could be over.
Buffon said: “Life is beautiful, another missed match or another missed World Cup won’t change my mind.
He added: "There are many ways to be important even if you are not a protagonist on the pitch. So come on great Salvatore, come on magic guys, come on Italy, my great love!"
Andrea Pirlo will take the captain's armband from his Juventus team-maye against England. Antonio Candreva replaced Buffon alongside head coach Cesare Prandelli at Italy's press conference ahead of the Group D clash.
"He twisted his ankle very lightly," Prandelli said of the 36-year-old Juve man. "It was a very, very light ankle twist. He is receiving therapy at the moment, but it is nothing serious."
However, Prandelli's words are in contrast to other reports emanating from the Italy camp, which claimed Buffon has suffered an ankle sprain and also hurt his knee in the incident.
Sirigu himself is not 100 per cent fit, however, having sustained severe rib bruising in training 10 days ago. It will also be only his second competitive match for Italy, with seven of his eight caps coming in friendlies.
Buffon's absence is a huge blow to an Italy side that has already lost full-back Mattia de Sciglio through injury.
It is hardly the ideal preparation for Saturday's match against an England side which Prandelli knows has the ability to hurt them on the attack.
"England have personality and psychological strength," he said. "They are very good at running, they are a fast team.
"The attackers have technical skills and are able to use the space available to them in the best way, so we will have to be very careful and we will have to try to control the midfield. That is going to be the key."
Prandelli, like England counterpart Roy Hodgson earlier on Friday evening, downplayed issues surrounding the pitch in Manaus.
Images emerged in the days leading up to Saturday's encounter that showed the surface to be in a shocking state, with over-fertilisation making the grass dry and led to brown patches.
Some of those areas appeared to be spray painted over on Thursday but, having trained on the Arena Amazonia surface for more than an hour, Prandelli had no concerns.
"The turf that had been described to me was in a very bad condition, but it is actually in very good condition," he said.
"It is not exceptional, but it is certainly good. As regards to the system of play I am going to use, it is always good to have a few lingering doubts on the night before because up until the very last minute the players must feel that they are still competing for a place on the squad.
"We don't want to give any competitive advantage to anybody."
- Sports & Recreation
- Cesare Prandelli
- Salvatore Sirigu