The Portuguese star wants to negotiate a new deal with Real Madrid because of a clause which means the club make more money from him than he does from them.
"The Portugal star’s current contract has a clause written into it which sees Real rake in 40 per cent of the player’s individual personal endorsements," the paper explains.
"Given that Ronaldo is one of the biggest stars in the sporting world, that effectively means he pays the club more out of his own pocket than Real actually pay him in wages."
Fairness rather than money is said to be the player's driving force in the renegotiation, but the upshot is that Ronaldo is "ready to quit" in the summer - with new United sponsors GM reportedly looking at backing a £55m bid.
Spain's El Confidencial claims that incoming Bayern Munich manager Pep Guardiola has made Liverpool striker Luis Suarez his top target for the summer.
The rumour has the tang of truth about it - and it's hard to see why anyone wouldn't want Suarez, given his outrageous talent - so it seems that Suarez's recent public statements dedicating himself to Liverpool will be put to the test.
In other words, he might as well order the Linguaphone CDs right away to start brushing up his German.
The Daily Mail reports an extraordinary story claiming that war has broken out at Stamford Bridge after manager Rafa Benitez criticised his Chelsea players following Sunday's defeat by Manchester City.
"Less than 24 hours after they were beaten 2-0 by champions Manchester City, the Spaniard told his players that their attitude had cost a series of managers the sack, then lectured them on their failure to grasp tactics and a lack of effort," the paper reports.
"But interim manager Benitez was stunned when one senior player suggested he might be at fault, given the club's success in winning the European Cup last May. 'We won the European Cup with this team,' the player said. A furious Benitez also accused the squad of under-performing since he replaced Roberto Di Matteo in November."
The identity of that "senior player" is not revealed, but the paper adds that Benitez then had a set-to with John Terry, who, "reminded Benitez that senior players have spoken to him about his managerial methods."
"A discussion that began with the best of intentions then descended into a heated discussion between the players and the interim coach," the report concludes.
If even half of it is true it's no wonder that Benitez was openly courting a move to Real Madrid at the end of last week.
The Daily Mirror claims that Manchester United are "on alert" after Robert Lewandowski's agent suggested that the Polish striker wants to leave Borussia Dortmund.
Cezary Kucharski points out that the Pole never stays anywhere more than two years but is already into his third season at the German champions. "Anyone who can read between the lines knows what that means," he said.
The Daily Mail claims that Chelsea are in talks to sign Southampton's 17-year-old left-back Luke Shaw for around £10m, with a loan-back deal likely, while the BBC claims, via Spain's Estadio Deportivo, that Manchester City are keen on Sevilla midfielder Geoffrey Kondogbia, who would cost £17m.