The 22-year-old forward fractured a vertebra in a collision with Juan Zuniga during Brazil’s World Cup quarter-final against Colombia last month.
Neymar, nominated for the Golden Ball despite missing their semi-final obliteration by Germany and the disappointing third-place play-off defeat by Netherlands, successfully passed a medical on his return to Catalonia on Tuesday.
A statement on the Barcelona website read: "The four World Cup semi-finalists Leo Messi, Javier Mascherano, Dani Alves and Neymar all trained with their colleagues on Tuesday.
"They returned to the club for their medical tests and all passed with flying colours, and are now set for three weeks of intense training in the build-up to the start of official matches in three weeks’ time."
Neymar scored 15 goals in 41 appearances in his first season at Camp Nou, after signing from boyhood club Santos for â¬87.2 million last summer.
Barcelona host Elche in their opening La Liga game, which takes place on August 24.