Toni Kroos, the esteemed midfielder for Real Madrid, recently announced his retirement, prompting both praise for his illustrious career and speculation about his impact on the team. While Kroos is widely regarded as one of the best midfielders in the history of the game, there is an intriguing trend that suggests Real Madrid performs better without him on the pitch.
In analyzing the data available on FBref’s playing time tables, it becomes apparent that Real Madrid has a better goal difference without Kroos than with him in most seasons. This surprising pattern raises the question of whether Kroos has been inadvertently holding his team back all along.
However, it is essential to consider the limitations of traditional plus-minus statistics in football. Unlike in sports like basketball or hockey, where plus-minus can provide valuable insights into player performance, football presents unique challenges. With more players on the pitch and fewer substitutions, isolating Kroos’s impact becomes more complex. Additionally, factors such as the quality of teammates, opponents, and external circumstances make it difficult to draw definitive conclusions from on-off statistics.
To overcome these challenges, researchers and data companies have started developing top-down player impact metrics that account for contextual factors. These adjusted plus-minus models aim to capture a player’s contribution beyond what happens on the ball. While Kroos’s unadjusted on-off figures may be puzzling, these new metrics offer a more comprehensive assessment of his impact.
One such model developed by Lars Magnus Hvattum ranks Kroos as Real Madrid’s 15th-best player. Although this may suggest that Real Madrid is generally better off without him, it still places Kroos among the top 500 players globally. Another model from data consultancy Goalimpact adjusts for context but still finds Kroos’s numbers to be a mystery.
The debate around Kroos’s impact extends beyond statistical models. Some critics argue that his style of play is outdated, emphasizing horizontal passes rather than the modern game’s verticality. However, others, like the legendary German midfielder Lotthar Matthaus, consider him one of Germany’s greatest footballers.
Ultimately, assessing player ratings requires a comprehensive approach that considers various indicators of player quality and tracks development over time. While top-down models offer valuable insights, they may take years to provide a complete picture of a player’s impact. A hybrid technique that combines bottom-up analysis with detailed on-ball stats can offer a more immediate assessment.
So, is Toni Kroos a hindrance or a vital asset to Real Madrid? The answer lies somewhere in between. While there may be aspects of his game that diminish his value, it is clear that his passing technique and trophy-winning experience have been invaluable to the team. As with many aspects of data science, there is still much to learn and explore.