Edinson Cavani’s situation is being complicated by a £2million pay-off that Manchester United will have to pay if they fail to trigger a one- year contact extension.
The Uruguayan striker signed a 12-month deal worth £200,000 a week when he arrived at Old Trafford in October after being released by Paris Saint-Germain.
The agreement also included the option of a further 12 months – but only if both parties agreed.
Cavani was also able to negotiate a kiss-off clause that would see him depart with a £2m golden handshake if United decided against keeping him at the club until the summer of 2022.
The 34-year-old forward can walk away for free at the end of the season – and Argentine giants Boca Juniors want to take him back to South America.
But Boca are unable to match his £10.5m-a-year salary at Old Trafford.
And Cavani can smell a lucrative final pay-day from United that would help cover his loss of earnings on moving to Buenos Aires.
Talks between player and club have become deadlocked because neither side is prepared to make a decision that will cost them millions.
The impasse could be broken in the next 10 days after Boca issued Cavani an ultimatum.
Argentine legend Juan Roman Riquelme is a vice-president of Boca and has been leading the charm offensive to land the former Palermo, Napoli and PSG talisman.
But the club’s board want to press ahead with alternative transfer arrangements should Riquelme’s efforts fail.
And they have given Cavani’s advisers a deadline for an answer.
Boca are in the market for a strike partner for Carlos Tevez and will move for Michael Estrada of Ecuadorian club Toluca if their bid to land Cavani is unsuccessful.