Paris Saint-Germain say they will take “appropriate action” after revealing that Neymar did not return for the first day of pre-season training.
The Brazilian star, who has been linked with a return to Barcelona in recent weeks, missed his country's successful Copa America campaign due to ruptured ankle ligaments.
However, despite his injury, the club have released a statement saying they expected him back on Monday but that he did not return as agreed.
"On Monday 8 July Neymar da Silva Santos Junior was due to return to pre-season activities with the Paris Saint-Germain senior squad," a club statement said.
"Paris Saint-Germain notes that Neymar Jr was not in attendance at the agreed time and place. This was without the club's prior authorisation.
"The club regrets this situation and will therefore take appropriate action."
However, the PSG forward's father Neymar Sr told Fox Sports Brazil that the club knew his son would not due back in France until July 15 due to charitable commitments.
"We have commercial and institutional events to carry out, events that the Neymar Institute has been doing for the last five years now," he said.
"PSG, with the presence of the president Nasser, have even participated personally in these events. For that reason, I don't understand the reason for the statement.
"Of course we are angry, because PSG have always been aware of the situation."
PSG released pictures of Neymar's team-mates, including the likes of Kylian Mbappe and Marco Verratti, as well as new signing Ander Herrera, going through routine medical checks upon their return to PSG.
Neymar became the world's most expensive player when PSG paid £200m to sign him from Barcelona in 2017.
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