Neymar cracked the fifth metatarsal of his right foot while playing for Paris Saint-Germain in their 3-0 Ligue 1 victory over Marseille on Sunday, reports Xinhua news agency.
The 26-year-old will undergo surgery in his homeland on Saturday after tests showed the injury was worse than first thought.
"It is a significant fracture to the bone in his foot," Brazil team doctor Rodrigo Lasmar told reporters in here on Thursday.
"There are several types of fractures. For a fracture of this type, many times it is unnoticed and it ends up being much bigger, as has happened to Neymar, there is no doubt.
"The best and only course of action is surgery because with a more conservative approach there would be a great chance that another fracture could occur within a short period of time. And we cannot run that risk," he added.
The injury rules Neymar out of the second leg of Paris Saint-Germain's Champions League round of 16 tie against Real Madrid in Paris on March 6.
It could also leave him with just two weeks to regain fitness ahead of the World Cup in Russia. Brazil play their first match against Switzerland in the southern port city of Rostov-on-Don on June 17.
"The recovery time is between two and a half and three months," Lasmar said.
"Every player is different. The intention is to monitor how the situation is and have regular control of the recovery," he added.
"Neymar is sad, but he understands that now he doesn't have any other options. He will work to be well as soon as possible. We will do everything possible for him to be ready as soon as possible."
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
