The 37-year-old has not reported back to training at Carrington, citing family reasons, which the club have accepted.

Ronaldo's absence comes amid informing United he wants to leave Old Trafford this summer if a suitable offer arrives.

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But United continue to insist that Ronaldo is not for sale.

According to Sky Sports News' Dharmesh Sheth, new United boss Erik ten Hag is talking to all the players individually about his plans and their ambitions as they return for pre-season - and that process will continue with Ronaldo when he returns.

Ronaldo was due to re-join his team-mates on Monday, but has instead been keeping fit at Portugal's training base - Cidade do Futebol - for the past few days.

Sky Sports News has been told Ronaldo's agent, Jorge Mendes, has spent the past few weeks selling the 'Cristiano effect' to clubs having compiled a dossier of his client's immense sponsorship, social media and 'new markets' influence.

Chelsea co-owner Todd Boehly is among the executives to listen to the pitch and is considering a move.

Bayern Munich, Barcelona and Napoli have also been engaged and while United insist Ronaldo is not for sale, that stance is expected to soften if a proposal from an overseas team is presented.

The club do not want the situation to overshadow Erik ten Hag's pre-season work or incomings, with full-back Tyrell Malacia unveiled as the Dutchman's first signing and Christian Eriksen verbally committing to join.

A basic agreement is in place with Barcelona for Frenkie de Jong, while advanced negotiations continue for Lisandro Martinez.

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Talks have also taken place with Ajax for forward Antony, but new boss Alfred Schreuder indicated: "He has a contract until 2025. I want to work with him, and the club knows this."

Ten Hag will have to expand his attacking targets if Ronaldo does exit with the club already concerned by their lack of goalscoring threat heading into the new campaign.

Ronaldo scored 24 times across all competitions last term, but United recorded their lowest-ever Premier League points tally.

If he misses the tour, it will be viewed as spelling the end of the Portugal international's second stint at the club.

United begin their pre-season schedule against Liverpool in Bangkok next Tuesday, before friendlies with Melbourne City, Crystal Palace and Aston Villa in Australia.

Where is Ronaldo and who can afford him?

Portuguese football expert Pedro Sepulveda speaking on Sky Sports News:

"If you look at the teams that can give Ronaldo a contract, there aren't many. Nor are there many teams who can compete for the Champions League. You have Bayern Munich who have said Ronaldo is not part of their project. In Spain, you have Real Madrid and you can't put Barcelona in the race. Ronaldo will never play for Barcelona and Real Madrid isn't interested in a player like Ronaldo anymore.

"In England is the only place I could see some opportunities - but can you see Ronaldo playing in the Premier League with another shirt that's not Man United? Can he be on another team? You have Liverpool and Chelsea - we already know the new Chelsea owner had a conversation with Jorge Mendes about Cristiano Ronaldo.

"I don't think we have to talk about the financials, look at the money he already has. It's not about the money, it's about the project.

"Ronaldo has the desire to play in United States too. It's a possibility in the future but not for this transfer window. These teams are in Ronaldo's head and they're in the fight for him."

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