Neymar tore knee ligaments in Brazil's 2-0 defeat to Uruguay in the South American 2026 FIFA World Cup qualifier on Tuesday.
The 31-year-old is set for a long layoff, having only just recently returned from an ankle injury that ended his Paris Saint Germain career in February.
Neymar joined Saudi Arabian side Al Hilal this summer and has scored once and provided three assists in five appearances so far.
Al Hilal posted on X: "The medical tests “NEYMAR ” underwent, confirmed the Anterior Cruciate Ligament and Meniscus tear injury in his knee.
"He will be going through surgery and then a treatment program that will be determined later.
"Return stronger Neymar."
The Brazilian FA (CBF) added: "The striker will undergo surgery, on a date yet to be set, to correct the injuries.
"The medical department of the Brazilian national team and Al Hilal are in constant contact and are aligned in the athlete's recovery."
Writing on Instagram, Neymar said: “It’s a very sad time, the worst.
“I know I’m strong, but this time I’m going to need my family and friends even more.
“It’s not easy to go through injury and surgery, imagine going through it all again after four months of recovery.”
Neymar is now likely to miss the rest of the season for Al Hilal and faces a race against time to be fit for next summer's Copa America.
