Real Madrid's biggest problem isn't Kylian Mbappe or their dire defence: Los Blancos' lack of a Toni Kroos replacement is holding Carlo Ancelotti's star-studded squad back

Madrid endured a poor season in 2022-23 - at least by their standards. They failed to win La Liga and bowed out of the Champions League to a rampant Manchester City in the semi-finals, with one of the main issues that year being the midfield. New signing Aurelien Tchouameni never fully settled, and after a mixture of injuries and personal issues, was forced out of the side. Kroos ended up playing as a No.6 - with usual bundle of energy Eduardo Camavinga stuck out at left back.

Kroos, for the first time in his career, was given the runaround. He was 32 at the time, and didn't possess the pace or athleticism of his team-mates. It was a disaster waiting to happen, and the individual errors added up, while some of his positioning was woeful. Madrid were constantly caught in transition, and by the end of the season, there were some calls for Kroos to retire. And with just one year remaining in his contract, few would have blamed him.

But he stayed all the same, and there was a sense from the summer that something might be brewing. Kroos had a swagger and cockiness about him, calling out players for making moves to Saudi Arabia while suggesting that new arrival Bellingham might not start right away. Brash? Certainly. But it was clear that Kroos meant business.

And so it proved, as Kroos was a man revived in 2023-24, benefitting from the change of system brought about by Bellingham's signing that led to Ancelotti deploying a four-man midfield. The England international's goals grabbed the headlines, but Bellingham's work-rate was also immense, meaning Madrid finally had legs in the middle. Federico Valverde's drop into a deeper role, meanwhile, meant that Kroos had less ground to cover. The balance was there; all Kroos had to do was pass.

And boy can Kroos pass. His numbers weren't just the best in the world; they were some of the most impressive that the game had ever seen. Per FBRef, he was in the 99th percentile among all midfielders in pass completion percentage, passes attempted and progressive passes last season. Everything ran through him, while his attacking numbers also spiked. He registered his most assists (10) for four years and his shot-creating actions also went up.

Kroos supposedly thought about continuing his career for a while. He admitted later on that although he had been considering retirement since the start of 2024, it took him until April to make a decision, and a further month to fully inform the club.

The reasons for that are perhaps many. His performances were immensely promising, and Madrid weren't about to lose anyone else in central midfield. Bellingham could only get better, while Valverde and Luka Modric were both also set to stick around.

And on a more personal level, there was other football to be played. Julian Nagelsmann had recalled him to the Germany squad for Euro 2024, which in turn had led to an upturn in their performances. As it turned out, had they not run into Spain in the quarter-final, there was every chance that the hosts could have won the whole thing.

Even after he announced his retirement, Kroos was repeatedly asked about the potential of reversing his decision. Surely, he couldn't walk away from this Germany team, with Nagelsmann penning a long-term contract. And with Mbappe on the way, who could resist the chance to play at least some part in Madrid's new era? But he stuck to his guns all the same.

In Valverde, Madrid thought they had a ready-made replacement. Kroos made a show of giving Valverde his No.8 shirt after Madrid won the Champions League final at Wembley - effectively declaring the Uruguayan his heir.

It felt like the right call, too. Valverde is a different kind of player, but his versatility and technique can't be denied. There had been a sense that he was always meant to be a deeper-lying player, with circumstances and the team's other needs preventing him from playing in his best spot.

The reality has been far different. Valverde isn't Kroos. The South American is frantic, an all-action midfielder if there ever was one. He is far more comfortable shooting from 30 yards than controlling the tempo of the midfield. He would rather run with the ball than pass it to someone else.

Crunch the numbers and it's clear. Valverde is in the 83rd percentile for pass completion percentage and 71st for progressive passes. This is not necessarily an indictment on him; he is a very good footballer, but he is not the same type of player as one of the game's greats.

But this isn't the fault of one man, either. Madrid's slight regression in 2024-25 is complex and difficult to pin down. Indeed, if it were easy, they would be winning every week.

Injuries, for one, haven't helped, but part of the problem here is very similar to the one that plagued Madrid in 2022-23; they don't control games in the same way. Without their main man in the middle, they get ripped apart in transition. It is how Barcelona battered them in back-to-back Clasicos, and is how first Lille and then Liverpool beat them in the Champions League.

Part of that, of course, is losing the ball in the wrong areas. They don't complete passes at a high enough clip, give the ball away more often and are then forced to recover. Another major component though, more simply, is the numerical disadvantage.

And it is here that we reach the Mbappe knock-on effect. Ancelotti has struggled immensely to figure out how to get all of his best attacking players on the pitch. His solution has been to play a 4-3-3, with Vinicius, Mbappe and Rodrygo up front, with Bellingham, Valverde and, when fit, Camavinga in the midfield. Now, instead of defending with four midfielders, Madrid defend with three.

However, Mbappe's lackadaisical attitude towards concepts such as 'pressing' and 'defence', the structure is all over the place. Bellingham has to do Mbappe's work and push higher up the pitch, so when he gets bypassed, Madrid are defending two against four. They are being overrun.

The solution, historically, would be to slow things down and keep the ball. That's what Kroos brought to this team. Madrid could still be hit on the break - it was pretty much the only way to beat them last year - but with a numerical advantage and a pass master in the middle, they often simply suffocated opponents. Put more simply: you can't get hit in transition if you always have the ball.

And that might yet happen again, but the reinforcements have to come from elsewhere, and a solution might be on the way. It looks inevitable, at this point, that Trent Alexander-Arnold will leave Liverpool and sign for Madrid as a free agent. His best position has become an object of fascination in the English press, a gruesome dissection to pour over on a weekly basis.

The Liverpool academy product is neither a central midfielder nor a traditional right-back. But if used correctly by Madrid, he could be the perfect Kroos replacement. It's easy to imagine Alexander-Arnold starting at right-back but then drifting into midfield while Madrid have possession and pinging the ball from deep. He performs such a role immensely well for both Liverpool and England. His pass completion percentage (74.1%) is significantly lower than Kroos', but that's because he is encouraged to play high-risk balls. His progressive passes per 90 minutes (8.28), are the best of any full-back in world football.

This is, once again, an imperfect fit, and there are admittedly defensive concerns that come with signing Alexander-Arnold. But if Madrid want someone to dictate from deep, pace the game, and ensure that they have control, Alexander-Arnold might be the closest thing football has to a Kroos replacement. His arrival - whether in the next two weeks or the summer - might be the only solution to a problem that is becoming clearer with every game that goes by.