It understood the 32-year-old feels he is being singled out for disproportionate treatment after prosecutors accused him of defrauding the authorities of €14.7 million (£12.8m).
A source claims the “outraged” Portugal international “feels great indignation” with all the speculation about his tax affairs and a sense of “injustice” at the allegations – which he contests – and has made a decision to leave Spain.
The Portuguese sports daily A Bola published a front-page story yesterday saying that Ronaldo was upset with the accusations made against him and that his decision was “irreversible.”
Earlier this week the player’s agency Gestifute released a statement which said: “’There is no tax evasion scheme ... There has never been any hiding nor any intention to hide anything.”
On Thursday Ronaldo, who only signed a new five-year contract in November, posted a picture of him with his fingers to his lips on Instagram with the caption: “Sometimes the best answer it’s to be quiet.”
The potential availability of the Portugal international, one of the most marketable players in the world, would alert a number of Europe’s top clubs, plus big-spending Chinese Super League sides looking to make a statement.
However, his Real contract is understood to have a €1 billion (£874m) buy-out clause and, in May, Forbes calculated his pre-tax salary as being close to £45m a year.
Ronaldo has helped Real win the Champions League three times, scoring twice in last month’s final as they became the first club to retain the title and he only the second player to score in three different finals. He is also the competition’s record goalscorer with 105.
He has also won two La Liga titles with Real, the club he joined from Manchester United for £80m in 2009.
Arch-rival Lionel Messi took a similar stance in threatening to quit Spain in 2014, also claiming he had been singled out for special treatment, when he was accused of concealing €4.1m (£3.5m) from the authorities. The Argentina captain was found guilty and subsequently lost an appeal against a 21-month prison sentence – under Spanish law sentences under two years are usually suspended – and a €2.1m (£1.8m) fine.
Ronaldo is currently with the Portugal squad in Kazan, Russia, preparing for the Confederations Cup.
He trained normally with the rest of the squad yesterday. Portugal, the defending European champions, play Mexico tomorrow in their Group A opener in the eight-nation competition that serves as a warm-up for next year’s World Cup in Russia.