Neymar was included in Carlo Ancelotti's 26-man squad for FIFA's flagship tournament, but now faces a race against time to play at what will be his fourth World Cup. 

Chelsea's Joao Pedro was the most high-profile omission for Brazil, with Neymar picked ahead of him despite not playing for Brazil in almost three years after sustaining an anterior cruciate ligament injury (ACL). 

The 34year-old suffered his latest issue during Santos' 3-0 defeat against Coritiba on 17 May and missed three games, though he was confident the injury was not a serious one. 

However, Lasmar has confirmed Neymar will not be available for Brazil's pre-World Cup friendlies against Panama and Egypt, while the Selecao's opener at the tournament against Morocco could also be beyond his reach.

"Neymar reported for duty yesterday here at ​Granja Comary, underwent all the medical tests, which concluded with an MRI scan revealing a ​grade-two calf injury, not just swelling. He is expected to be cleared in ⁠two to three weeks," Lasmar said.

Brazil also takes on Haiti on 19 June in Philadelphia before it concludes its Group C campaign against Scotland five days later at Hard Rock Stadium in Miami. 

Ancelotti will be hoping Neymar can feature for his side sooner rather than later, given he is his nation's all-time top scorer with 79 goals in 128 appearances. 

Neymar has netted eight goals and provided three assists in 13 matches at the World Cup, with only Ronaldo Nazario (19), Pele (18) and Jairzinho (12) directly contributing more at the finals for Brazil. 

He is also one of three players to score and assist in the last three World Cups, along with former Barcelona team-mate Lionel Messi and Croatia's Luka Modric.