It was not long ago that it looked like Casemiro would be leaving Manchester United in disgrace, ushered out the back door and out of European football for good, consigned to history as one of the club's worst transfer errors. Instead, he is set to leave with his head held high, showing that, contrary to Jamie Carragher's brutal assessment, the football never left him after all.United's announcement on Thursday that Casemiro is set to leave the club in the summer when his contract runs out was perfectly timed, a rare case of the Red Devils getting something right. It came after one of the Brazilian's best displays of the season against Manchester City, when he received a standing ovation from the Old Trafford crowd and heard his name reverberate around the stadium. And it came as speculation was growing about whether or not the club would trigger his one-year contract extension, which was threatening to become a distraction from the pursuit of that all-important top-four finish. Now Casemiro has plenty of time to look for a new club and United have more time to begin their midfield rebuild and target players who are approaching their prime years.It means that the Brazilian can focus on finishing his up-and-down United career on a real high and get the farewell he deserves for fighting his way back into the team and proving everyone wrong...Casemiro had an enormous impact on United when he arrived from Real Madrid in August 2022. The team had lost their first two games of the season to Brighton and Brentford - getting hammered 4-0 by the Bees - and he instantly beefed up their midfield and sprinkled the squad with his win-at-all-costs mentality, honed from his eight years at the heart of Madrid's multiple Champions League-winning machine.He was fundamental to United finishing third in the Premier League, reaching the FA Cup final and winning the Carabao Cup, which he celebrated on the Wembley pitch with just as much gusto as any trophy he had won with Madrid. Indeed, in an interview with AS last year Casemiro described the 2022-23 campaign as his best performance on an individual level of his entire career.But playing over 50 games in a season took its toll on his body and the following campaign he looked like he was struggling to keep up with the pace of the Premier League while he also suffered two injuries. The rest of the squad was also obliterated by injuries and by the end of the campaign Casemiro was either asked to anchor an inexperienced midfield or play at centre-back, a position he had never previously played.It was when playing at centre-back that Crystal Palace ran riot over United at Selhurst Park, hammering United 4-0. Casemiro was badly exposed by Michael Olise and that was when Carragher tore into the Brazilian on Sky Sports by saying: "I always remember something when I retired: 'Leave the football before the football leaves you'. "The football's left him at this top level. He needs to call it a day at this level of football and move. A man of that level should not be going through what he's going through now, he needs to call it a day."Casemiro was then dropped from the squad for the FA Cup final. He was expected to leave that summer, especially if a club from Saudi Arabia came calling. No acceptable offers came in, however, and the Brazilian made a decent start to the following campaign. But it all unravelled again when he made a mistake leading to a goal against Liverpool and was hauled off at half-time by Erik ten Hag for 20-year-old debutant Toby Collyer.The Brazilian didn't start another league game under Ten Hag for six weeks. Interim boss Ruud van Nistelrooy did lean on the veteran heavily in his four games in charge after Ten Hag was sacked but Ruben Amorim seemed to also write off the player, making him an unused substitute for 12 games in a sequence of 15.Casemiro returned to the team against Tottenham, but only after an injury crisis afflicted Kobbie Mainoo and Collyer. And the coach gave a typically honest but brutal assessment of the player when speaking to TNT Sports Mexico around that time. He said:  "We understand that Casemiro has other things nowadays. The intelligence he has, understanding the game, understanding where the ball is going to fall but we’re in a league that I can see, even in European competitions, the difference in intensity is big. And so, I feel that this team also needs players with a very high intensity."Add GOAL.com as a preferred source on Google to see more of our reportingBut once Casemiro got a run of games he began to prove his coach wrong and locked down his place in Amorim's line-up for the crucial stage of the season, playing a pivotal role in the run to the Europa League final. He contributed to three of the goals in the incredible extra-time comeback win over Lyon and scored in the semi-final first leg against Athletic Club. He also earned a recall to the Brazil squad under Carlo Ancelotti, his old boss in Madrid.He has remained unmovable this season, starting 19 of United's 22 league games. And whenever he has not started, the team has badly suffered, losing against Grimsby in the Carabao Cup, Brighton in the FA Cup and Manchester City, Brentford and Aston Villa in the Premier League. He has contributed four goals and an assist from holding midfield and was outstanding in United's first win at Anfield in a decade and most recently against City.In October Amorim hailed Casemiro for digging in to reclaim his place in the team. He said: "He fought and he worked and now he's back in the national team. He gives a lot of experience, he is an example for everyone. We understand that football can change really fast. You just need to work. You're going to play if you do the right things."But that does not mean that United are wrong to be letting Casemiro go in the summer. He turns 34 next month and is among the club's highest-paid players. Reports of his actual salary vary from £325,000 per week to £375,000 per week, although he has been subject to a 25 percent reduction in his wage like every other player in the squad in the three seasons United have failed to qualify for the Champions League. The Athletic estimates that between his £70m transfer fee from Real Madrid and his salary over four years, he has cost the club a total of £119m.Extending his contract by a year would have meant on the same terms as his initial agreement, costing the club between £16.5m and 19.5m annually. That figure would rise even more in the event United qualified for the Champions League. It has been reported that when Sir Jim Ratcliffe found out about Casemiro's salary, he raised the alarm and effectively used it as an example of the club's avarice before he arrived. In an era where Ratcliffe has taken away free lunches from employees and made up to 450 people redundant in order to save costs, Casemiro's salary was increasingly hard to justify. United sources have stressed that Casemiro’s departure will enable additional capacity to invest in strengthening the squad as the club continues to build towards regular and sustained success.Even with Casemiro's impressive resurgence, it is hard to not argue that United signing him in the first place smacked of desperation. The right thing to do now is to build for the future and target players who can lead United's midfield for the next decade, players such as England international Elliot Anderson and Palace midfielder Adam Wharton or Brighton's Carlos Baleba, who was a target last summer.Casemiro said "I will carry Manchester United with me throughout my entire life" and he has also left his mark on the club. He might have been a stop-gap solution and an expensive one at that, but the Brazilian has brought a lot of joy to United fans and given them many moments they will never forget.He took the club back into the Champions League, helped deliver a first trophy in six years and then reversed his own decline to give them some semblance of stability. Now he has four months left and United fave should savour them as it will not be easy to replace a player of his experience or with his utter refusal to throw in the towel.