Neymar is considering a formal complaint to FIFA against his former club Barcelona over an unpaid loyalty bonus, according to Sky sources.
Sky Sports News understands that the most expensive signing in world football feels "very bad" over the withheld payment, according to a source in Spain close to the player.
Barcelona are refusing to pay a £23m bonus to Neymar's father following a contract renewal last year.
Neymar completed a world record move to Paris Saint-Germain on Thursday after Barcelona received full payment of his €222m (£200m) buyout clause.
It is understood Neymar's lawyers have yet to lodge paperwork to world football's governing body but the option remains under consideration.
FIFA will not comment on specific cases but a spokesperson told Sky Sports News: "As a general rule, and without prejudice to the right of any player or club to seek redress before a civil court for employment-related disputes, the decision-making bodies of FIFA would be competent unless the parties have explicitly agreed for such dispute to be decided by an independent arbitration tribunal."
Barcelona spokesman Josep Vives told a news conference: "The club will not pay the bonus to Neymar's father.
"There were three conditions: the player must not negotiate his departure from the club during the month before the bonus became payable, he must demonstrate his desire to fulfil his contract, and that we would not pay out the bonus before September 1, to ensure the transfer window was closed.
"Now that we know that none of these three conditions were met, we will not honour that bonus."