Grateful for the vacancy at Manchester United, Andrey Santos leaves Chelsea after concluding the midfield had become too crowded for him.Moises Caicedo’s new deal underlined his status in the starting line-up. Enzo Fernandez will only be allowed to leave if his club are offered £120million. Reece James is another option in the middle, along with Romeo Lavia and Dario Essugo, both of whom are expected to stay unless a surprise market opens up for a pair whose last campaigns were disrupted by fitness problems. Chelsea’s interest in Granit Xhaka tells us they are still in the market for more, and that is before getting to the Cobham prospects.Santos did not mind spending a season as an understudy while the club were competing in the Champions League. But now they were facing a campaign without Europe entirely, the 22-year-old Brazilian requested talks to discuss him departing out of a desire for more meaningful minutes.Chelsea sympathised, agreed, and, several weeks ago, gave his representatives Sports Invest UK permission to start canvassing potential suitors. Andrey Santos with his wife Yngryd at his official Manchester United unveiling this week United have spent £48million plus £2m in add-ons on Santos, bringing an end to the 22-year-old’s three years at ChelseaEvidently, no limitations were placed on where he could and could not go, with a domestic rival in United securing this tidy midfielder for the relatively sensible sum of £50million.For Chelsea, that is worth £48m up front with £2m in achievable add-ons and 10 per cent of any future sale. It is a significant profit on the £16m fee they paid to Vasco da Gama in 2023.However, a few fans around Stamford Bridge are not happy.They do not blame Santos for wanting to leave, but they do think they should have extracted more money out of United because they see his potential. United are not signing the completed package, but rather what Santos could become, and time on the pitch should hopefully aid his progress.Chelsea had chances to sell Santos before. Last summer, they turned down a £45m approach from West Ham. United were sniffing around then, too. But Chelsea liked what they were seeing in flashes.The passes played forwards, including the first-time ones around the corner which created chances and showed his eye. The willingness to defend, and the duels won. Enzo Maresca told us last August that he wanted Santos to stay as a midfield option, and so he did. Then Chelsea boss Enzo Maresca wasn’t happy after Santos’ mistake led to Trevoh Chalobah being sent off with the Blues 1-0 up against Brighton, a game they went on to lose 3-1 Chelsea admired Santos’ intent to play passes forward and his willingness to defendYet the last season was not too smooth for Santos, who was at fault on more than one occasion as Chelsea went from being talked up as title contenders to finishing 10th in the Premier League.In September, when Chelsea hosted Brighton, Santos received a pass while filling in for James as the captain received treatment on the sidelines. Santos’ first touch was terrible, sending him backwards and allowing Kaoru Mitoma to press him aggressively. Santos desperately slid towards the ball in a bid to send it towards Robert Sanchez or Trevoh Chalobah. Instead, he gave it to Diego Gomez, and Chalobah brought him down before receiving a red card for denying a goalscoring opportunity.Chelsea were winning 1-0 at the time of Chalobah’s dismissal. Down to 10 men, they ended up falling to a 3-1 defeat. Maresca was not pleased with Chalobah or Santos.Absent from Chelsea’s next two games, Santos then started away at Nottingham Forest, only to be hooked at half-time as Maresca’s side were goalless. They went on to win 3-0. From then on, Maresca only handed starts to Santos in the less glamourous games, such as Qarabag away in the Champions League, Wolves away in the Premier League and Cardiff away in the Carabao Cup.After Maresca’s exit, Liam Rosenior’s arrival was supposed to spark something in Santos. He had thrived under him at Strasbourg, and Rosenior described Santos as tactically excellent when we asked for his take. Initially, Santos was a big winner of that appointment. The starts came one after another.Then arrived Chelsea versus Burnley in February. Rosenior revealed afterwards how one of his players failed to fulfil their marking assignment as the visitors’ 6ft 1in striker Zian Flemming scored a free header in stoppage time to secure a 1-1 draw. Rosenior would not confirm who that culprit was. When the away side won another corner a minute later, however, it was suddenly Santos who was marking Flemming.Even Rosenior seemed to lose trust in Santos as time wore on. Maybe we should not read too much into that, of course. The only players who impressed on Rosenior’s watch were Joao Pedro and Jorrel Hato. But it felt telling that the footballer he knew better than everyone else was being benched. Santos was an unused substitute for Rosenior’s final two games in charge. Last season wasn’t smooth for Santos, who was named in Brazil’s preliminary squad for the World Cup but didn’t make the final cut Santos with United director of football Jason Wilcox – it’s time for him to seize his opportunity and make Chelsea regret selling himWith Calum McFarlane taking over as interim head coach, one of Santos’ final starts in a Chelsea shirt arrived in April when Manchester City visited. With Fernandez suspended, he stepped in, but was the one who was supposed to be marking Nico O’Reilly when he headed in to hand City their decisive lead. A big moment and a big mistake.So there is room for improvement, but then United know that. He is young, talented, and has more experience than many other 22-year-olds. If Chelsea are to regret selling Santos, though, it is over to the Brazilian to step up and seize this opportunity at Old Trafford.