The endgame of Cristiano Ronaldo's Manchester United career is now in play. Despite the club's public position stating that the Portugal forward will not be leaving Old Trafford this summer, it is increasingly likely that he has already made his final appearance in a United shirt.

A delayed return to the first day of preseason training on Monday, due to family reasons, follows after sources told ESPN at the weekend that Ronaldo wants to leave United less than a year after returning to Old Trafford, 12 years after initially leaving the club for Real Madrid. It is also unclear as to whether Ronaldo will fly to Bangkok on Friday with the rest of the squad for the start of United's 2½-week tour of Thailand and Australia.

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Erik ten Hag was always going to have a bumpy ride in his early months as United's new manager due to the mountain of problems he inherited from his predecessors, but a frenzy of speculation around the future of his most high-profile player is a distraction he could do without.

Sources have told ESPN, however, that United would be open to offloading Ronaldo, 37, if a club outside the Premier League is prepared to take on the final 12 months of his £500,000-a-week contract. As reported by ESPN on Saturday, there is tentative interest from Bayern Munich and Napoli, while Chelsea are also keen to sign the former Real Madrid and Juventus player.

A move to Chelsea would, right now, be unpalatable to United due to the club's determination to qualify for the 2023-24 Champions League. With Chelsea being a direct competitor for a top-four finish in the Premier League, there is little prospect of Ronaldo being allowed to move to Stamford Bridge, but there would be less resistance within the United hierarchy to a deal being struck with Bayern, Napoli or any other European team that may yet emerge as a potential destination.

And while the consistent message from United throughout the summer has been that Ronaldo is part of new boss Ten Hag's plans and will be at the club next season, sources have said that there is an acceptance that allowing him to leave now will ultimately help accelerate the former Ajax coach's rebuilding programme. But perhaps for the first time in his two spells at United, Ronaldo has let the team down by waiting until now -- just five weeks before the start of the new season -- to signal his desire to leave Old Trafford in order to play in the Champions League next season.

On June 3, Ronaldo spoke to United's official website and, without directly saying that he would stay, gave a strong hint that he would remain at the club by speaking of wanting to "win trophies next year" and giving Ten Hag "time to make changes." Sources have told ESPN, though, that there has been a constant sense behind the scenes at United this summer that Ronaldo was waiting for the right moment to push for a move and that there would be few tears shed in the dressing room if he chose to leave, pointing to tensions within the squad centred around Ronaldo and his demanding personality.

But while many of his teammates may be happy to see Ronaldo go, by allowing news of his unhappiness at the club to emerge now, he has left United on the back foot in terms of finding a replacement. United are already toiling in the transfer market this summer with no new signings being made before all the squad return to training. Sources have said that Feyenoord left-back Tyrell Malacia will complete a move within the next 48 hours, Christian Eriksen has agreed to join the club on a three-year deal and there is a hope that Ajax defender Lisandro Martinez will also arrive this week, but primary target Frenkie de Jong has still to be signed from Barcelona and there have been no additions to the attacking options. If Ronaldo goes, United will have to find a replacement for the player who was their 24-goal top scorer last season. Ajax winger Antony is high on the list of targets, but the 22-year-old would be a gamble rather than the proven goal scorer United would clearly need.

But by keeping United waiting until now to make his intentions clear, Ronaldo has prevented the club from competing for forwards who have already made big moves. Richarlison (Everton to Tottenham Hotspur) and Gabriel Jesus (Manchester City to Arsenal) would have offered proven options, while United could have made a more concerted effort to thwart Liverpool's move to sign Darwin Nunez from Benfica. As it stands now, they could attempt to beat Barcelona to Bayern Munich's Robert Lewandowski or even offer Paris Saint-Germain the chance to take Neymar off their hands, but those are the kinds of last-minute, high-profile deals that United are trying to consign to the past. But Ronaldo has ensured that everything must now be on the table.

Nobody comes out of this situation well. Ronaldo should have made his intentions clear at the end of last season, but United and Ten Hag have also had opportunities to force the issue and deal with it much sooner. The end result of the communications failure on both sides is a situation that leaves both parties in a race against time, which suits neither.

Ronaldo must find a club ready and willing to fund his signing, while United have to identify a replacement and sign him, at the same time as attempting to bolster Ten Hag's squad with the reinforcements they already desperately needed.

But one thing is certain: Ronaldo's time at United is up.